Code
C1236
HUMMER
C — Chassis
Low System Supply Voltage
Views:
UK: 12
EN: 22
RU: 18
AI status
Completed
Completed
100%
Causes
- Weak or discharged battery
- Poor battery terminal or cable connections (corrosion, loose)
- Faulty battery ground or chassis ground strap
- Faulty alternator or charging system (failed diode/regulator)
- High-resistance wiring or connector in the supply feed to the control module
- Parasitic drain causing low battery
Symptoms
- Illumination of ABS, traction control, or other chassis warning lamps
- Intermittent loss of system function (ABS/traction/stability)
- Stored or current DTCs related to low voltage or communication
- Hard or inconsistent brake feel if ABS disabled
- Possible difficulty starting if battery is very low
What to check
- Visually inspect battery, terminals and cables for corrosion, tightness and damage
- Measure battery voltage at rest, with ignition ON, during cranking, and with engine running
- Measure voltage at the affected module power and ground pins while the code is set
- Perform a charging system test (alternator output and regulator check)
- Inspect wiring harness and connectors to the module for damage, pin corrosion, or loose terminals
- Check main engine/chassis ground points for tightness and corrosion
Signal parameters
- Battery resting voltage: typically 12.4–12.8 V (healthy, fully charged)
- Ignition ON (engine off) module supply: ~12.0–12.8 V
- Engine running supply (alternator charging): typically 13.5–14.8 V
- Cranking (start) voltage: should usually remain above ~9.0–10.0 V; prolonged drops below ~8–9 V indicate battery/connection problem
- Fault trigger threshold: module detects supply below expected operating range (often below ~11–11.5 V) or large transient drops
Diagnostic algorithm
- Retrieve freeze frame and related DTCs with a capable scan tool. Note conditions when C1236 set (ignition state, engine running, load).
- Visually inspect battery condition, hold-down, and both positive/negative terminals. Clean and tighten as required.
- Measure battery voltage at battery posts with ignition OFF. A healthy charged battery should read ~12.4–12.8 V. If below ~12.0 V, charge or replace battery.
- With ignition ON (engine off), measure voltage at the battery and at the module power supply pin. Compare readings. Significant voltage drop at the module indicates wiring or connector resistance.
- Start engine and measure charging voltage at battery and module. Expect ~13.5–14.8 V. If alternator not charging, test alternator/drive belt and regulator.
- Perform voltage drop tests: between battery positive and module supply, and between battery negative and module ground, both with ignition ON and during a simulated load. Voltage drop should be minimal (
- Wiggle test harness and connectors while watching supply voltage and live data; look for intermittent changes that reproduce the fault.
- If parasitic drain suspected, perform a battery parasitic draw test to identify excessive current draw when vehicle is off.
- Repair any corroded terminals, damaged wiring, poor grounds, or replace faulty alternator/battery as indicated by tests.
- After repairs, clear codes and perform a road test or required drive cycle while monitoring supply voltage and related system data. Confirm code does not return.
- Only consider module replacement if wiring, grounds, battery and charging system are confirmed good and the fault persists.
Likely causes
- Low battery state of charge or failing battery
- Loose or corroded battery terminals
- Open or high-resistance ground to module
- Failed alternator/regulator not maintaining system voltage
- Damaged supply or ground wiring to the module
Fault status
Status
Low system supply voltage detected by control module. Check battery, charging system, wiring, and grounds before replacing modules.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
C1236
HYUNDAI
C — Chassis
Front Height Sensor Abnormal. | EMS Indicates Invalid Engine Speed | High Pressure Accumulator Low Pressure Error
Views:
UK: 22
EN: 27
RU: 25
AI status
Completed
Completed
100%
Causes
- Weak or discharged battery
- Poor battery terminal or cable connections (corrosion, loose)
- Faulty battery ground or chassis ground strap
- Faulty alternator or charging system (failed diode/regulator)
- High-resistance wiring or connector in the supply feed to the control module
- Parasitic drain causing low battery
Symptoms
- Illumination of ABS, traction control, or other chassis warning lamps
- Intermittent loss of system function (ABS/traction/stability)
- Stored or current DTCs related to low voltage or communication
- Hard or inconsistent brake feel if ABS disabled
- Possible difficulty starting if battery is very low
What to check
- Visually inspect battery, terminals and cables for corrosion, tightness and damage
- Measure battery voltage at rest, with ignition ON, during cranking, and with engine running
- Measure voltage at the affected module power and ground pins while the code is set
- Perform a charging system test (alternator output and regulator check)
- Inspect wiring harness and connectors to the module for damage, pin corrosion, or loose terminals
- Check main engine/chassis ground points for tightness and corrosion
Signal parameters
- Battery resting voltage: typically 12.4–12.8 V (healthy, fully charged)
- Ignition ON (engine off) module supply: ~12.0–12.8 V
- Engine running supply (alternator charging): typically 13.5–14.8 V
- Cranking (start) voltage: should usually remain above ~9.0–10.0 V; prolonged drops below ~8–9 V indicate battery/connection problem
- Fault trigger threshold: module detects supply below expected operating range (often below ~11–11.5 V) or large transient drops
Diagnostic algorithm
- Retrieve freeze frame and related DTCs with a capable scan tool. Note conditions when C1236 set (ignition state, engine running, load).
- Visually inspect battery condition, hold-down, and both positive/negative terminals. Clean and tighten as required.
- Measure battery voltage at battery posts with ignition OFF. A healthy charged battery should read ~12.4–12.8 V. If below ~12.0 V, charge or replace battery.
- With ignition ON (engine off), measure voltage at the battery and at the module power supply pin. Compare readings. Significant voltage drop at the module indicates wiring or connector resistance.
- Start engine and measure charging voltage at battery and module. Expect ~13.5–14.8 V. If alternator not charging, test alternator/drive belt and regulator.
- Perform voltage drop tests: between battery positive and module supply, and between battery negative and module ground, both with ignition ON and during a simulated load. Voltage drop should be minimal (
- Wiggle test harness and connectors while watching supply voltage and live data; look for intermittent changes that reproduce the fault.
- If parasitic drain suspected, perform a battery parasitic draw test to identify excessive current draw when vehicle is off.
- Repair any corroded terminals, damaged wiring, poor grounds, or replace faulty alternator/battery as indicated by tests.
- After repairs, clear codes and perform a road test or required drive cycle while monitoring supply voltage and related system data. Confirm code does not return.
- Only consider module replacement if wiring, grounds, battery and charging system are confirmed good and the fault persists.
Likely causes
- Low battery state of charge or failing battery
- Loose or corroded battery terminals
- Open or high-resistance ground to module
- Failed alternator/regulator not maintaining system voltage
- Damaged supply or ground wiring to the module
Fault status
Status
Low system supply voltage detected by control module. Check battery, charging system, wiring, and grounds before replacing modules.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
C1236
LAND ROVER
C — Chassis
loss of signal wheel speed left rear
Views:
UK: 15
EN: 18
RU: 18
AI status
Completed
Completed
100%
Causes
- Weak or discharged battery
- Poor battery terminal or cable connections (corrosion, loose)
- Faulty battery ground or chassis ground strap
- Faulty alternator or charging system (failed diode/regulator)
- High-resistance wiring or connector in the supply feed to the control module
- Parasitic drain causing low battery
Symptoms
- Illumination of ABS, traction control, or other chassis warning lamps
- Intermittent loss of system function (ABS/traction/stability)
- Stored or current DTCs related to low voltage or communication
- Hard or inconsistent brake feel if ABS disabled
- Possible difficulty starting if battery is very low
What to check
- Visually inspect battery, terminals and cables for corrosion, tightness and damage
- Measure battery voltage at rest, with ignition ON, during cranking, and with engine running
- Measure voltage at the affected module power and ground pins while the code is set
- Perform a charging system test (alternator output and regulator check)
- Inspect wiring harness and connectors to the module for damage, pin corrosion, or loose terminals
- Check main engine/chassis ground points for tightness and corrosion
Signal parameters
- Battery resting voltage: typically 12.4–12.8 V (healthy, fully charged)
- Ignition ON (engine off) module supply: ~12.0–12.8 V
- Engine running supply (alternator charging): typically 13.5–14.8 V
- Cranking (start) voltage: should usually remain above ~9.0–10.0 V; prolonged drops below ~8–9 V indicate battery/connection problem
- Fault trigger threshold: module detects supply below expected operating range (often below ~11–11.5 V) or large transient drops
Diagnostic algorithm
- Retrieve freeze frame and related DTCs with a capable scan tool. Note conditions when C1236 set (ignition state, engine running, load).
- Visually inspect battery condition, hold-down, and both positive/negative terminals. Clean and tighten as required.
- Measure battery voltage at battery posts with ignition OFF. A healthy charged battery should read ~12.4–12.8 V. If below ~12.0 V, charge or replace battery.
- With ignition ON (engine off), measure voltage at the battery and at the module power supply pin. Compare readings. Significant voltage drop at the module indicates wiring or connector resistance.
- Start engine and measure charging voltage at battery and module. Expect ~13.5–14.8 V. If alternator not charging, test alternator/drive belt and regulator.
- Perform voltage drop tests: between battery positive and module supply, and between battery negative and module ground, both with ignition ON and during a simulated load. Voltage drop should be minimal (
- Wiggle test harness and connectors while watching supply voltage and live data; look for intermittent changes that reproduce the fault.
- If parasitic drain suspected, perform a battery parasitic draw test to identify excessive current draw when vehicle is off.
- Repair any corroded terminals, damaged wiring, poor grounds, or replace faulty alternator/battery as indicated by tests.
- After repairs, clear codes and perform a road test or required drive cycle while monitoring supply voltage and related system data. Confirm code does not return.
- Only consider module replacement if wiring, grounds, battery and charging system are confirmed good and the fault persists.
Likely causes
- Low battery state of charge or failing battery
- Loose or corroded battery terminals
- Open or high-resistance ground to module
- Failed alternator/regulator not maintaining system voltage
- Damaged supply or ground wiring to the module
Fault status
Status
Low system supply voltage detected by control module. Check battery, charging system, wiring, and grounds before replacing modules.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
C1236
MITSUBISHI
C — Chassis
FL inlet valve
Views:
UK: 15
EN: 22
RU: 18
AI status
Completed
Completed
100%
Causes
- Weak or discharged battery
- Poor battery terminal or cable connections (corrosion, loose)
- Faulty battery ground or chassis ground strap
- Faulty alternator or charging system (failed diode/regulator)
- High-resistance wiring or connector in the supply feed to the control module
- Parasitic drain causing low battery
Symptoms
- Illumination of ABS, traction control, or other chassis warning lamps
- Intermittent loss of system function (ABS/traction/stability)
- Stored or current DTCs related to low voltage or communication
- Hard or inconsistent brake feel if ABS disabled
- Possible difficulty starting if battery is very low
What to check
- Visually inspect battery, terminals and cables for corrosion, tightness and damage
- Measure battery voltage at rest, with ignition ON, during cranking, and with engine running
- Measure voltage at the affected module power and ground pins while the code is set
- Perform a charging system test (alternator output and regulator check)
- Inspect wiring harness and connectors to the module for damage, pin corrosion, or loose terminals
- Check main engine/chassis ground points for tightness and corrosion
Signal parameters
- Battery resting voltage: typically 12.4–12.8 V (healthy, fully charged)
- Ignition ON (engine off) module supply: ~12.0–12.8 V
- Engine running supply (alternator charging): typically 13.5–14.8 V
- Cranking (start) voltage: should usually remain above ~9.0–10.0 V; prolonged drops below ~8–9 V indicate battery/connection problem
- Fault trigger threshold: module detects supply below expected operating range (often below ~11–11.5 V) or large transient drops
Diagnostic algorithm
- Retrieve freeze frame and related DTCs with a capable scan tool. Note conditions when C1236 set (ignition state, engine running, load).
- Visually inspect battery condition, hold-down, and both positive/negative terminals. Clean and tighten as required.
- Measure battery voltage at battery posts with ignition OFF. A healthy charged battery should read ~12.4–12.8 V. If below ~12.0 V, charge or replace battery.
- With ignition ON (engine off), measure voltage at the battery and at the module power supply pin. Compare readings. Significant voltage drop at the module indicates wiring or connector resistance.
- Start engine and measure charging voltage at battery and module. Expect ~13.5–14.8 V. If alternator not charging, test alternator/drive belt and regulator.
- Perform voltage drop tests: between battery positive and module supply, and between battery negative and module ground, both with ignition ON and during a simulated load. Voltage drop should be minimal (
- Wiggle test harness and connectors while watching supply voltage and live data; look for intermittent changes that reproduce the fault.
- If parasitic drain suspected, perform a battery parasitic draw test to identify excessive current draw when vehicle is off.
- Repair any corroded terminals, damaged wiring, poor grounds, or replace faulty alternator/battery as indicated by tests.
- After repairs, clear codes and perform a road test or required drive cycle while monitoring supply voltage and related system data. Confirm code does not return.
- Only consider module replacement if wiring, grounds, battery and charging system are confirmed good and the fault persists.
Likely causes
- Low battery state of charge or failing battery
- Loose or corroded battery terminals
- Open or high-resistance ground to module
- Failed alternator/regulator not maintaining system voltage
- Damaged supply or ground wiring to the module
Fault status
Status
Low system supply voltage detected by control module. Check battery, charging system, wiring, and grounds before replacing modules.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
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Code
C1236
Other
C — Chassis
Speed Wheel LR Input Signal Missing
Views:
UK: 30
EN: 45
RU: 45
AI status
Completed
Completed
100%
Causes
- Weak or discharged battery
- Poor battery terminal or cable connections (corrosion, loose)
- Faulty battery ground or chassis ground strap
- Faulty alternator or charging system (failed diode/regulator)
- High-resistance wiring or connector in the supply feed to the control module
- Parasitic drain causing low battery
Symptoms
- Illumination of ABS, traction control, or other chassis warning lamps
- Intermittent loss of system function (ABS/traction/stability)
- Stored or current DTCs related to low voltage or communication
- Hard or inconsistent brake feel if ABS disabled
- Possible difficulty starting if battery is very low
What to check
- Visually inspect battery, terminals and cables for corrosion, tightness and damage
- Measure battery voltage at rest, with ignition ON, during cranking, and with engine running
- Measure voltage at the affected module power and ground pins while the code is set
- Perform a charging system test (alternator output and regulator check)
- Inspect wiring harness and connectors to the module for damage, pin corrosion, or loose terminals
- Check main engine/chassis ground points for tightness and corrosion
Signal parameters
- Battery resting voltage: typically 12.4–12.8 V (healthy, fully charged)
- Ignition ON (engine off) module supply: ~12.0–12.8 V
- Engine running supply (alternator charging): typically 13.5–14.8 V
- Cranking (start) voltage: should usually remain above ~9.0–10.0 V; prolonged drops below ~8–9 V indicate battery/connection problem
- Fault trigger threshold: module detects supply below expected operating range (often below ~11–11.5 V) or large transient drops
Diagnostic algorithm
- Retrieve freeze frame and related DTCs with a capable scan tool. Note conditions when C1236 set (ignition state, engine running, load).
- Visually inspect battery condition, hold-down, and both positive/negative terminals. Clean and tighten as required.
- Measure battery voltage at battery posts with ignition OFF. A healthy charged battery should read ~12.4–12.8 V. If below ~12.0 V, charge or replace battery.
- With ignition ON (engine off), measure voltage at the battery and at the module power supply pin. Compare readings. Significant voltage drop at the module indicates wiring or connector resistance.
- Start engine and measure charging voltage at battery and module. Expect ~13.5–14.8 V. If alternator not charging, test alternator/drive belt and regulator.
- Perform voltage drop tests: between battery positive and module supply, and between battery negative and module ground, both with ignition ON and during a simulated load. Voltage drop should be minimal (
- Wiggle test harness and connectors while watching supply voltage and live data; look for intermittent changes that reproduce the fault.
- If parasitic drain suspected, perform a battery parasitic draw test to identify excessive current draw when vehicle is off.
- Repair any corroded terminals, damaged wiring, poor grounds, or replace faulty alternator/battery as indicated by tests.
- After repairs, clear codes and perform a road test or required drive cycle while monitoring supply voltage and related system data. Confirm code does not return.
- Only consider module replacement if wiring, grounds, battery and charging system are confirmed good and the fault persists.
Likely causes
- Low battery state of charge or failing battery
- Loose or corroded battery terminals
- Open or high-resistance ground to module
- Failed alternator/regulator not maintaining system voltage
- Damaged supply or ground wiring to the module
Fault status
Status
Low system supply voltage detected by control module. Check battery, charging system, wiring, and grounds before replacing modules.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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