Code
P0703
Generic
P — Powertrain
Brake Switch B Circuit
Views:
UK: 20
EN: 53
RU: 53
AI status
Completed
Completed
100%
Causes
- Failed or intermittent brake light/switch B (mechanical or internal electrical failure)
- Open or shorted wiring between switch and control module
- Corroded, bent, or loose connector or terminal at the switch or module
- Poor ground or missing reference/pull-up voltage at the input
- Aftermarket wiring or recent repairs damaged circuit
- Faulty body/control module input (rare)
Symptoms
- Brake lights may not illuminate or may be intermittent
- Cruise control may not engage or may disengage immediately
- Inability to shift out of Park on vehicles with shift interlock tied to brake switch
- Malfunction indicator lamp (MIL)/warning lamp may be set
- Starter inhibited on vehicles that require brake pedal to start
What to check
- Scan for related codes and capture freeze-frame/live data for brake switch status
- Visually inspect brake switch, mounting, and connector for damage, corrosion, pinched wires or poor fit
- Check brake lights operation while an assistant presses the pedal
- Verify connector pins are straight and terminals are clean and tight
- Perform continuity and resistance checks across switch terminals with pedal pressed/released
- Backprobe signal wire at switch and module while operating pedal to observe signal changes with a multimeter or scope
Signal parameters
- Typical digital switch: two-state signal (ON/OFF). Expected: closed = continuity to ground (≈0 Ω) or near 0V; open = pulled to reference voltage (≈5V or battery voltage depending on vehicle)
- Common reference voltages: 5 V pull-up or battery around 9–14 V (varies by manufacturer)
- Open-circuit = very high resistance/infinite, Short-to-ground = ~0 V constant, Short-to-battery = ≈12 V constant
- If available, an oscilloscope should show a clean, stable transition when pedal pressed/released
Diagnostic algorithm
- Retrieve code(s) and live data; note whether code is continuous or intermittent and any freeze-frame conditions
- Visually inspect switch, pedal linkage, bracket, and wiring harness (focus where harness flexes at pedal and bulkhead)
- Confirm brake light operation — if lights do not work, suspect switch or power/ground to switch
- With ignition ON, backprobe switch connector: verify reference voltage (5 V or battery) and ground presence; press/release pedal and watch signal change
- Check continuity/resistance across switch terminals: closed (pedal depressed) should show low resistance; open (released) should show high resistance
- If signal does not change, disconnect connector and measure at connector to help isolate between switch and module
- Wiggle test wiring while monitoring signal to reproduce intermittent faults
- Repair or replace damaged wiring, terminals, or the brake switch as indicated (use OEM-style switch and correct adjustment procedure)
- After repairs, clear codes and roadtest to confirm code does not return and function is normal
- If wiring and switch verify OK and fault persists, test module input and associated grounds; consider module replacement only after exhausting wiring/switch checks
Likely causes
- Corroded/loose connector at the brake switch
- Switch out of adjustment or worn plunger
- Broken or pinched wire in harness near pedal or bulkhead
- Contaminated switch contacts causing intermittent operation
Fault status
Status
Control module detected an unexpected/no signal or circuit fault on Brake Switch B input (open/short/intermittent). This can disable cruise, shift interlock, or other systems tied to brake input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Workshop ManualLAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
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Workshop ManualYour experience will help others
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Code
P0703
GWM
P — Powertrain
- Malfunction in the brake torque reduction sensor circuit B
Views:
UK: 2
EN: 10
RU: 6
AI status
Completed
Completed
100%
Causes
- Failed or intermittent brake light/switch B (mechanical or internal electrical failure)
- Open or shorted wiring between switch and control module
- Corroded, bent, or loose connector or terminal at the switch or module
- Poor ground or missing reference/pull-up voltage at the input
- Aftermarket wiring or recent repairs damaged circuit
- Faulty body/control module input (rare)
Symptoms
- Brake lights may not illuminate or may be intermittent
- Cruise control may not engage or may disengage immediately
- Inability to shift out of Park on vehicles with shift interlock tied to brake switch
- Malfunction indicator lamp (MIL)/warning lamp may be set
- Starter inhibited on vehicles that require brake pedal to start
What to check
- Scan for related codes and capture freeze-frame/live data for brake switch status
- Visually inspect brake switch, mounting, and connector for damage, corrosion, pinched wires or poor fit
- Check brake lights operation while an assistant presses the pedal
- Verify connector pins are straight and terminals are clean and tight
- Perform continuity and resistance checks across switch terminals with pedal pressed/released
- Backprobe signal wire at switch and module while operating pedal to observe signal changes with a multimeter or scope
Signal parameters
- Typical digital switch: two-state signal (ON/OFF). Expected: closed = continuity to ground (≈0 Ω) or near 0V; open = pulled to reference voltage (≈5V or battery voltage depending on vehicle)
- Common reference voltages: 5 V pull-up or battery around 9–14 V (varies by manufacturer)
- Open-circuit = very high resistance/infinite, Short-to-ground = ~0 V constant, Short-to-battery = ≈12 V constant
- If available, an oscilloscope should show a clean, stable transition when pedal pressed/released
Diagnostic algorithm
- Retrieve code(s) and live data; note whether code is continuous or intermittent and any freeze-frame conditions
- Visually inspect switch, pedal linkage, bracket, and wiring harness (focus where harness flexes at pedal and bulkhead)
- Confirm brake light operation — if lights do not work, suspect switch or power/ground to switch
- With ignition ON, backprobe switch connector: verify reference voltage (5 V or battery) and ground presence; press/release pedal and watch signal change
- Check continuity/resistance across switch terminals: closed (pedal depressed) should show low resistance; open (released) should show high resistance
- If signal does not change, disconnect connector and measure at connector to help isolate between switch and module
- Wiggle test wiring while monitoring signal to reproduce intermittent faults
- Repair or replace damaged wiring, terminals, or the brake switch as indicated (use OEM-style switch and correct adjustment procedure)
- After repairs, clear codes and roadtest to confirm code does not return and function is normal
- If wiring and switch verify OK and fault persists, test module input and associated grounds; consider module replacement only after exhausting wiring/switch checks
Likely causes
- Corroded/loose connector at the brake switch
- Switch out of adjustment or worn plunger
- Broken or pinched wire in harness near pedal or bulkhead
- Contaminated switch contacts causing intermittent operation
Fault status
Status
Control module detected an unexpected/no signal or circuit fault on Brake Switch B input (open/short/intermittent). This can disable cruise, shift interlock, or other systems tied to brake input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P0703
HUMMER
P — Powertrain
Brake Switch Circuit Malfunction
Views:
UK: 6
EN: 16
RU: 22
AI status
Completed
Completed
100%
Causes
- Failed or intermittent brake light/switch B (mechanical or internal electrical failure)
- Open or shorted wiring between switch and control module
- Corroded, bent, or loose connector or terminal at the switch or module
- Poor ground or missing reference/pull-up voltage at the input
- Aftermarket wiring or recent repairs damaged circuit
- Faulty body/control module input (rare)
Symptoms
- Brake lights may not illuminate or may be intermittent
- Cruise control may not engage or may disengage immediately
- Inability to shift out of Park on vehicles with shift interlock tied to brake switch
- Malfunction indicator lamp (MIL)/warning lamp may be set
- Starter inhibited on vehicles that require brake pedal to start
What to check
- Scan for related codes and capture freeze-frame/live data for brake switch status
- Visually inspect brake switch, mounting, and connector for damage, corrosion, pinched wires or poor fit
- Check brake lights operation while an assistant presses the pedal
- Verify connector pins are straight and terminals are clean and tight
- Perform continuity and resistance checks across switch terminals with pedal pressed/released
- Backprobe signal wire at switch and module while operating pedal to observe signal changes with a multimeter or scope
Signal parameters
- Typical digital switch: two-state signal (ON/OFF). Expected: closed = continuity to ground (≈0 Ω) or near 0V; open = pulled to reference voltage (≈5V or battery voltage depending on vehicle)
- Common reference voltages: 5 V pull-up or battery around 9–14 V (varies by manufacturer)
- Open-circuit = very high resistance/infinite, Short-to-ground = ~0 V constant, Short-to-battery = ≈12 V constant
- If available, an oscilloscope should show a clean, stable transition when pedal pressed/released
Diagnostic algorithm
- Retrieve code(s) and live data; note whether code is continuous or intermittent and any freeze-frame conditions
- Visually inspect switch, pedal linkage, bracket, and wiring harness (focus where harness flexes at pedal and bulkhead)
- Confirm brake light operation — if lights do not work, suspect switch or power/ground to switch
- With ignition ON, backprobe switch connector: verify reference voltage (5 V or battery) and ground presence; press/release pedal and watch signal change
- Check continuity/resistance across switch terminals: closed (pedal depressed) should show low resistance; open (released) should show high resistance
- If signal does not change, disconnect connector and measure at connector to help isolate between switch and module
- Wiggle test wiring while monitoring signal to reproduce intermittent faults
- Repair or replace damaged wiring, terminals, or the brake switch as indicated (use OEM-style switch and correct adjustment procedure)
- After repairs, clear codes and roadtest to confirm code does not return and function is normal
- If wiring and switch verify OK and fault persists, test module input and associated grounds; consider module replacement only after exhausting wiring/switch checks
Likely causes
- Corroded/loose connector at the brake switch
- Switch out of adjustment or worn plunger
- Broken or pinched wire in harness near pedal or bulkhead
- Contaminated switch contacts causing intermittent operation
Fault status
Status
Control module detected an unexpected/no signal or circuit fault on Brake Switch B input (open/short/intermittent). This can disable cruise, shift interlock, or other systems tied to brake input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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0
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Code
P0703
LAND ROVER
P — Powertrain
brake switch input failure
Views:
UK: 7
EN: 13
RU: 19
AI status
Completed
Completed
100%
Causes
- Failed or intermittent brake light/switch B (mechanical or internal electrical failure)
- Open or shorted wiring between switch and control module
- Corroded, bent, or loose connector or terminal at the switch or module
- Poor ground or missing reference/pull-up voltage at the input
- Aftermarket wiring or recent repairs damaged circuit
- Faulty body/control module input (rare)
Symptoms
- Brake lights may not illuminate or may be intermittent
- Cruise control may not engage or may disengage immediately
- Inability to shift out of Park on vehicles with shift interlock tied to brake switch
- Malfunction indicator lamp (MIL)/warning lamp may be set
- Starter inhibited on vehicles that require brake pedal to start
What to check
- Scan for related codes and capture freeze-frame/live data for brake switch status
- Visually inspect brake switch, mounting, and connector for damage, corrosion, pinched wires or poor fit
- Check brake lights operation while an assistant presses the pedal
- Verify connector pins are straight and terminals are clean and tight
- Perform continuity and resistance checks across switch terminals with pedal pressed/released
- Backprobe signal wire at switch and module while operating pedal to observe signal changes with a multimeter or scope
Signal parameters
- Typical digital switch: two-state signal (ON/OFF). Expected: closed = continuity to ground (≈0 Ω) or near 0V; open = pulled to reference voltage (≈5V or battery voltage depending on vehicle)
- Common reference voltages: 5 V pull-up or battery around 9–14 V (varies by manufacturer)
- Open-circuit = very high resistance/infinite, Short-to-ground = ~0 V constant, Short-to-battery = ≈12 V constant
- If available, an oscilloscope should show a clean, stable transition when pedal pressed/released
Diagnostic algorithm
- Retrieve code(s) and live data; note whether code is continuous or intermittent and any freeze-frame conditions
- Visually inspect switch, pedal linkage, bracket, and wiring harness (focus where harness flexes at pedal and bulkhead)
- Confirm brake light operation — if lights do not work, suspect switch or power/ground to switch
- With ignition ON, backprobe switch connector: verify reference voltage (5 V or battery) and ground presence; press/release pedal and watch signal change
- Check continuity/resistance across switch terminals: closed (pedal depressed) should show low resistance; open (released) should show high resistance
- If signal does not change, disconnect connector and measure at connector to help isolate between switch and module
- Wiggle test wiring while monitoring signal to reproduce intermittent faults
- Repair or replace damaged wiring, terminals, or the brake switch as indicated (use OEM-style switch and correct adjustment procedure)
- After repairs, clear codes and roadtest to confirm code does not return and function is normal
- If wiring and switch verify OK and fault persists, test module input and associated grounds; consider module replacement only after exhausting wiring/switch checks
Likely causes
- Corroded/loose connector at the brake switch
- Switch out of adjustment or worn plunger
- Broken or pinched wire in harness near pedal or bulkhead
- Contaminated switch contacts causing intermittent operation
Fault status
Status
Control module detected an unexpected/no signal or circuit fault on Brake Switch B input (open/short/intermittent). This can disable cruise, shift interlock, or other systems tied to brake input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
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Send to email
Code
P0703
MERCEDES-BENZ
P — Powertrain
Torque Converter/Brake Switch B Circuit Malfunction
Views:
UK: 12
EN: 25
RU: 40
AI status
Completed
Completed
100%
Causes
- Failed or intermittent brake light/switch B (mechanical or internal electrical failure)
- Open or shorted wiring between switch and control module
- Corroded, bent, or loose connector or terminal at the switch or module
- Poor ground or missing reference/pull-up voltage at the input
- Aftermarket wiring or recent repairs damaged circuit
- Faulty body/control module input (rare)
Symptoms
- Brake lights may not illuminate or may be intermittent
- Cruise control may not engage or may disengage immediately
- Inability to shift out of Park on vehicles with shift interlock tied to brake switch
- Malfunction indicator lamp (MIL)/warning lamp may be set
- Starter inhibited on vehicles that require brake pedal to start
What to check
- Scan for related codes and capture freeze-frame/live data for brake switch status
- Visually inspect brake switch, mounting, and connector for damage, corrosion, pinched wires or poor fit
- Check brake lights operation while an assistant presses the pedal
- Verify connector pins are straight and terminals are clean and tight
- Perform continuity and resistance checks across switch terminals with pedal pressed/released
- Backprobe signal wire at switch and module while operating pedal to observe signal changes with a multimeter or scope
Signal parameters
- Typical digital switch: two-state signal (ON/OFF). Expected: closed = continuity to ground (≈0 Ω) or near 0V; open = pulled to reference voltage (≈5V or battery voltage depending on vehicle)
- Common reference voltages: 5 V pull-up or battery around 9–14 V (varies by manufacturer)
- Open-circuit = very high resistance/infinite, Short-to-ground = ~0 V constant, Short-to-battery = ≈12 V constant
- If available, an oscilloscope should show a clean, stable transition when pedal pressed/released
Diagnostic algorithm
- Retrieve code(s) and live data; note whether code is continuous or intermittent and any freeze-frame conditions
- Visually inspect switch, pedal linkage, bracket, and wiring harness (focus where harness flexes at pedal and bulkhead)
- Confirm brake light operation — if lights do not work, suspect switch or power/ground to switch
- With ignition ON, backprobe switch connector: verify reference voltage (5 V or battery) and ground presence; press/release pedal and watch signal change
- Check continuity/resistance across switch terminals: closed (pedal depressed) should show low resistance; open (released) should show high resistance
- If signal does not change, disconnect connector and measure at connector to help isolate between switch and module
- Wiggle test wiring while monitoring signal to reproduce intermittent faults
- Repair or replace damaged wiring, terminals, or the brake switch as indicated (use OEM-style switch and correct adjustment procedure)
- After repairs, clear codes and roadtest to confirm code does not return and function is normal
- If wiring and switch verify OK and fault persists, test module input and associated grounds; consider module replacement only after exhausting wiring/switch checks
Likely causes
- Corroded/loose connector at the brake switch
- Switch out of adjustment or worn plunger
- Broken or pinched wire in harness near pedal or bulkhead
- Contaminated switch contacts causing intermittent operation
Fault status
Status
Control module detected an unexpected/no signal or circuit fault on Brake Switch B input (open/short/intermittent). This can disable cruise, shift interlock, or other systems tied to brake input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 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