P1258

Code

BUICK P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: BUICK

Type: P — Powertrain

Views: UK: 19 EN: 22 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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Code

P1258

CADILLAC P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: CADILLAC

Type: P — Powertrain

Views: UK: 20 EN: 24 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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Code

P1258

CHEVROLET P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: CHEVROLET

Type: P — Powertrain

Views: UK: 15 EN: 22 RU: 16

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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Code

P1258

CHRYSLER P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: CHRYSLER

Type: P — Powertrain

Views: UK: 19 EN: 23 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

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Code

P1258

FORD P — Powertrain

Pedal Correlation PDS1 and PDS2

Brand: FORD

Type: P — Powertrain

Views: UK: 18 EN: 22 RU: 18

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

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Code

P1258

Generic P — Powertrain

Pedal Correlation PDS1 and PDS2

Brand: Generic

Type: P — Powertrain

Views: UK: 17 EN: 23 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

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Code

P1258

GM P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: GM

Type: P — Powertrain

Views: UK: 17 EN: 28 RU: 18

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

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Code

P1258

GMC P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: GMC

Type: P — Powertrain

Views: UK: 20 EN: 38 RU: 23

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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Code

P1258

HUMMER P — Powertrain

Engine Coolant Overtemperature - above 268F - Protection Mode Active

Brand: HUMMER

Type: P — Powertrain

Views: UK: 8 EN: 15 RU: 8

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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Code

P1258

LINCOLN P — Powertrain

Pedal Correlation PDS1 and PDS2

Brand: LINCOLN

Type: P — Powertrain

Views: UK: 19 EN: 23 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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Code

P1258

MERCURY P — Powertrain

Pedal Correlation PDS1 and PDS2

Brand: MERCURY

Type: P — Powertrain

Views: UK: 19 EN: 22 RU: 18

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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Code

P1258

OLDSMOBILE P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: OLDSMOBILE

Type: P — Powertrain

Views: UK: 17 EN: 24 RU: 16

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

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Code

P1258

Other P — Powertrain

Pedal Correlation PDS1 and PDS2

Brand: Other

Type: P — Powertrain

Views: UK: 19 EN: 25 RU: 18

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

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Code

P1258

SATURN P — Powertrain

Engine Coolant Overtemperature Protection Mode Active

Brand: SATURN

Type: P — Powertrain

Views: UK: 20 EN: 25 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

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Code

P1258

VOLKSWAGEN P — Powertrain

Engine Coolant System Valve Short To B+

Brand: VOLKSWAGEN

Type: P — Powertrain

Views: UK: 17 EN: 26 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Actual engine coolant overheating (high coolant temperature)
Coolant level low or air trapped in cooling system
Faulty engine coolant temperature (ECT) sensor or wiring
Thermostat stuck closed or partially closed
Cooling fan(s) not operating or fan control circuit fault
Water pump failure or restricted coolant flow

Symptoms

Illuminated MIL/engine warning lamp
Reduced engine power or limp/protection mode active
High engine temperature gauge reading or temp warning message
Electric cooling fans not running when expected
Heater performance may be abnormal
Possible coolant leaks, boiling, or steam from engine bay

What to check

Visually inspect coolant level (engine cold) and look for obvious leaks
Check for steam, boiled coolant, or white residue around hoses and radiator
Scan for stored and pending DTCs and read freeze frame data
Record live data: coolant temperature, engine RPM, vehicle speed, fan status/command, thermostat position if available
Check cooling fan operation (commanded vs actual) with engine cold start and when reaching operating temp
Inspect radiator, hoses and water pump for leaks, flow, noise or contamination

Signal parameters

Engine coolant temperature (°C or °F) — idle, warm-up, under load
Fan command (ECM output) and fan RPM or fan status (on/off)
Battery/alternator voltage at fan relay and ECM with fan commanded
Thermostat opening indicator (if available) or radiator inlet/outlet temps
Engine RPM and vehicle speed at time of overtemp event (freeze frame)
Intake air temp and ambient temperature for context

Diagnostic algorithm

Safety: allow engine to cool before opening cooling system; relieve pressure carefully. Wear eye protection.
Use a scan tool to retrieve all DTCs and freeze frame; note coolant temp at fault and any related codes.
With a cold engine, verify coolant level and correct concentration; top to spec and pressure test the system for leaks (pressure tester).
Start engine and monitor coolant temp, fan commands, and fan operation. Force fan on via scan tool (if supported) to confirm fan, relay, fuse, and wiring are functional.
If fan does not run when commanded, test fan motor directly on bench or with fused 12V to confirm operation; test relay/fuse and wiring to ECM.
If fans operate correctly, check for circulation: with engine warmed, feel upper and lower radiator hoses for flow; a stuck thermostat often results in cold hose(s) or no flow. Replace thermostat if it fails to open.
Inspect radiator for blockage and verify water pump function (coolant flow, unusual noises, bearing/wobble). Replace as needed.
Verify ECT sensor accuracy by comparing scanner temperature reading to an infrared thermometer on thermostat housing or using a lab meter; if sensor out of spec, inspect wiring and replace sensor if required.
If a recent coolant service was performed, bleed air from the system per manufacturer procedure to remove airlocks that can cause local overheating.
Clear codes after repairs and perform a road test under load, monitoring temps and fan behavior to confirm normal operation and that P1258 does not return.
If all hardware and sensors check OK but the ECM reports protection mode with valid inputs, check for ECM software updates or consult technical service bulletins; replace ECM only if confirmed faulty per manufacturer procedure.

Likely causes

Low coolant level or leak causing insufficient cooling
Failed electric cooling fan or failed fan relay/fuse
Faulty ECT sensor giving false high readings or intermittent signal
Thermostat failed closed preventing coolant circulation
Obstructed radiator (debris, collapsed hose, clogged core) or failed water pump
Cooling system airlock after recent service or inadequate bleed

Fault status

⚠️ Status

Engine Coolant Overtemperature Protection Mode Active — ECM has limited engine operation due to detected/high coolant temperature or cooling system failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

Send to email