Code
P0724
Generic
P — Powertrain
Brake Switch B Circuit High
Views:
UK: 21
EN: 20
RU: 20
AI status
Completed
Completed
100%
Causes
- Failed or misadjusted brake light / brake pedal switch (Brake Switch B)
- Open or shorted wiring (short to battery/ignition voltage) on the switch circuit
- Corroded, loose, or damaged connector/pins at switch or control module
- Faulty body control module (BCM), engine control module (ECM) or transmission control module (TCM) input circuit
- Blown fuse or poor ground elsewhere causing unusual voltage on the circuit
- Aftermarket wiring or tapped circuits creating backfeed
Symptoms
- Brake lights may be stuck on or off, or behave intermittently
- Cruise control disabled or will not engage
- ABS/ESC or traction control warnings may illuminate
- Gear shift interlock or start/stop related issues (cannot shift out of park or engine won't start in some vehicles)
- Erratic transmission torque converter lockup or shift behavior (if input used by TCM)
What to check
- Read and record freeze frame and live data with a scan tool (brake switch B status/voltage)
- Visually inspect brake switch, connector, and wiring for damage, corrosion, or disconnection
- Operate brake pedal while observing switch operation and brake lights
- Backprobe the switch connector and measure voltage/logic signal with a multimeter
- Check continuity between switch and control module input pin, and for shorts to battery
- Verify proper ground(s) related to the switch and module
Signal parameters
- Typical idle (switch open) voltage: ~0 V (ground) or ~12 V depending on vehicle design — check vehicle wiring: some switches pull the input to ground when closed, others to battery voltage
- When brake pedal actuated the input should change state (toggle between low and high).
- Expected voltage change should be rapid and stable with pedal travel; intermittent or floating voltages indicate wiring/switch faults
- No high resistance (>1–2 ohm under mechanical connectors aside) between switch and module for power/ground circuits
Diagnostic algorithm
- Retrieve freeze frame and note ignition key state, battery voltage, and related codes. Check for multiple brake-switch related codes.
- Perform visual inspection of switch, harness, and connectors at the brake pedal and module. Repair obvious damage.
- With key ON (engine off) observe live data for Brake Switch B status. Press and release pedal — note expected status change and compare to Brake Switch A if present.
- Backprobe the switch connector. With multimeter measure voltage on the switch signal lead relative to ground with pedal released and pressed. Verify expected low/high transition.
- If the signal is high when it should be low, disconnect the brake switch. Measure voltage at the module input pin with the switch disconnected; if still high, suspect short to battery or module fault.
- Check continuity between switch signal pin and module input pin. Check for short to battery (voltage present when circuit should be open) or short to ground when it should be high.
- Inspect and test related fuses and grounds. Wiggle test harness while monitoring signal for intermittent faults.
- If wiring and connectors check good, substitute or bench-test a known-good brake switch. Replace switch if it fixes the fault.
- If replacement switch does not clear the issue, test/replace the receiving control module input or repair short in harness. Consult wiring diagrams and module pinouts before module replacement.
- Clear codes, perform functional tests and road test to confirm repair. Re-scan for codes and monitor live data again.
Likely causes
- Defective brake switch (most common)
- Connector pin pushed out/corroded at brake switch or module
- Short to battery voltage in harness near pedal or junction
- Intermittent open/short in harness due to rubbing/chafing
Fault status
Status
Brake Switch B Circuit High — control module detects higher-than-expected voltage on the Brake Switch B input. Check switch, wiring, connectors, and module input for short-to-voltage or faulty switch.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P0724
GWM
P — Powertrain
- High indicator of brake torque reduction sensor circuit B
Views:
UK: 2
EN: 2
RU: 1
AI status
Completed
Completed
100%
Causes
- Failed or misadjusted brake light / brake pedal switch (Brake Switch B)
- Open or shorted wiring (short to battery/ignition voltage) on the switch circuit
- Corroded, loose, or damaged connector/pins at switch or control module
- Faulty body control module (BCM), engine control module (ECM) or transmission control module (TCM) input circuit
- Blown fuse or poor ground elsewhere causing unusual voltage on the circuit
- Aftermarket wiring or tapped circuits creating backfeed
Symptoms
- Brake lights may be stuck on or off, or behave intermittently
- Cruise control disabled or will not engage
- ABS/ESC or traction control warnings may illuminate
- Gear shift interlock or start/stop related issues (cannot shift out of park or engine won't start in some vehicles)
- Erratic transmission torque converter lockup or shift behavior (if input used by TCM)
What to check
- Read and record freeze frame and live data with a scan tool (brake switch B status/voltage)
- Visually inspect brake switch, connector, and wiring for damage, corrosion, or disconnection
- Operate brake pedal while observing switch operation and brake lights
- Backprobe the switch connector and measure voltage/logic signal with a multimeter
- Check continuity between switch and control module input pin, and for shorts to battery
- Verify proper ground(s) related to the switch and module
Signal parameters
- Typical idle (switch open) voltage: ~0 V (ground) or ~12 V depending on vehicle design — check vehicle wiring: some switches pull the input to ground when closed, others to battery voltage
- When brake pedal actuated the input should change state (toggle between low and high).
- Expected voltage change should be rapid and stable with pedal travel; intermittent or floating voltages indicate wiring/switch faults
- No high resistance (>1–2 ohm under mechanical connectors aside) between switch and module for power/ground circuits
Diagnostic algorithm
- Retrieve freeze frame and note ignition key state, battery voltage, and related codes. Check for multiple brake-switch related codes.
- Perform visual inspection of switch, harness, and connectors at the brake pedal and module. Repair obvious damage.
- With key ON (engine off) observe live data for Brake Switch B status. Press and release pedal — note expected status change and compare to Brake Switch A if present.
- Backprobe the switch connector. With multimeter measure voltage on the switch signal lead relative to ground with pedal released and pressed. Verify expected low/high transition.
- If the signal is high when it should be low, disconnect the brake switch. Measure voltage at the module input pin with the switch disconnected; if still high, suspect short to battery or module fault.
- Check continuity between switch signal pin and module input pin. Check for short to battery (voltage present when circuit should be open) or short to ground when it should be high.
- Inspect and test related fuses and grounds. Wiggle test harness while monitoring signal for intermittent faults.
- If wiring and connectors check good, substitute or bench-test a known-good brake switch. Replace switch if it fixes the fault.
- If replacement switch does not clear the issue, test/replace the receiving control module input or repair short in harness. Consult wiring diagrams and module pinouts before module replacement.
- Clear codes, perform functional tests and road test to confirm repair. Re-scan for codes and monitor live data again.
Likely causes
- Defective brake switch (most common)
- Connector pin pushed out/corroded at brake switch or module
- Short to battery voltage in harness near pedal or junction
- Intermittent open/short in harness due to rubbing/chafing
Fault status
Status
Brake Switch B Circuit High — control module detects higher-than-expected voltage on the Brake Switch B input. Check switch, wiring, connectors, and module input for short-to-voltage or faulty switch.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P0724
HUMMER
P — Powertrain
Brake Switch Circuit High Input
Views:
UK: 12
EN: 13
RU: 11
AI status
Completed
Completed
100%
Causes
- Failed or misadjusted brake light / brake pedal switch (Brake Switch B)
- Open or shorted wiring (short to battery/ignition voltage) on the switch circuit
- Corroded, loose, or damaged connector/pins at switch or control module
- Faulty body control module (BCM), engine control module (ECM) or transmission control module (TCM) input circuit
- Blown fuse or poor ground elsewhere causing unusual voltage on the circuit
- Aftermarket wiring or tapped circuits creating backfeed
Symptoms
- Brake lights may be stuck on or off, or behave intermittently
- Cruise control disabled or will not engage
- ABS/ESC or traction control warnings may illuminate
- Gear shift interlock or start/stop related issues (cannot shift out of park or engine won't start in some vehicles)
- Erratic transmission torque converter lockup or shift behavior (if input used by TCM)
What to check
- Read and record freeze frame and live data with a scan tool (brake switch B status/voltage)
- Visually inspect brake switch, connector, and wiring for damage, corrosion, or disconnection
- Operate brake pedal while observing switch operation and brake lights
- Backprobe the switch connector and measure voltage/logic signal with a multimeter
- Check continuity between switch and control module input pin, and for shorts to battery
- Verify proper ground(s) related to the switch and module
Signal parameters
- Typical idle (switch open) voltage: ~0 V (ground) or ~12 V depending on vehicle design — check vehicle wiring: some switches pull the input to ground when closed, others to battery voltage
- When brake pedal actuated the input should change state (toggle between low and high).
- Expected voltage change should be rapid and stable with pedal travel; intermittent or floating voltages indicate wiring/switch faults
- No high resistance (>1–2 ohm under mechanical connectors aside) between switch and module for power/ground circuits
Diagnostic algorithm
- Retrieve freeze frame and note ignition key state, battery voltage, and related codes. Check for multiple brake-switch related codes.
- Perform visual inspection of switch, harness, and connectors at the brake pedal and module. Repair obvious damage.
- With key ON (engine off) observe live data for Brake Switch B status. Press and release pedal — note expected status change and compare to Brake Switch A if present.
- Backprobe the switch connector. With multimeter measure voltage on the switch signal lead relative to ground with pedal released and pressed. Verify expected low/high transition.
- If the signal is high when it should be low, disconnect the brake switch. Measure voltage at the module input pin with the switch disconnected; if still high, suspect short to battery or module fault.
- Check continuity between switch signal pin and module input pin. Check for short to battery (voltage present when circuit should be open) or short to ground when it should be high.
- Inspect and test related fuses and grounds. Wiggle test harness while monitoring signal for intermittent faults.
- If wiring and connectors check good, substitute or bench-test a known-good brake switch. Replace switch if it fixes the fault.
- If replacement switch does not clear the issue, test/replace the receiving control module input or repair short in harness. Consult wiring diagrams and module pinouts before module replacement.
- Clear codes, perform functional tests and road test to confirm repair. Re-scan for codes and monitor live data again.
Likely causes
- Defective brake switch (most common)
- Connector pin pushed out/corroded at brake switch or module
- Short to battery voltage in harness near pedal or junction
- Intermittent open/short in harness due to rubbing/chafing
Fault status
Status
Brake Switch B Circuit High — control module detects higher-than-expected voltage on the Brake Switch B input. Check switch, wiring, connectors, and module input for short-to-voltage or faulty switch.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P0724
LAND ROVER
P — Powertrain
Brake switch B - high circuit
Views:
UK: 12
EN: 11
RU: 9
AI status
Completed
Completed
100%
Causes
- Failed or misadjusted brake light / brake pedal switch (Brake Switch B)
- Open or shorted wiring (short to battery/ignition voltage) on the switch circuit
- Corroded, loose, or damaged connector/pins at switch or control module
- Faulty body control module (BCM), engine control module (ECM) or transmission control module (TCM) input circuit
- Blown fuse or poor ground elsewhere causing unusual voltage on the circuit
- Aftermarket wiring or tapped circuits creating backfeed
Symptoms
- Brake lights may be stuck on or off, or behave intermittently
- Cruise control disabled or will not engage
- ABS/ESC or traction control warnings may illuminate
- Gear shift interlock or start/stop related issues (cannot shift out of park or engine won't start in some vehicles)
- Erratic transmission torque converter lockup or shift behavior (if input used by TCM)
What to check
- Read and record freeze frame and live data with a scan tool (brake switch B status/voltage)
- Visually inspect brake switch, connector, and wiring for damage, corrosion, or disconnection
- Operate brake pedal while observing switch operation and brake lights
- Backprobe the switch connector and measure voltage/logic signal with a multimeter
- Check continuity between switch and control module input pin, and for shorts to battery
- Verify proper ground(s) related to the switch and module
Signal parameters
- Typical idle (switch open) voltage: ~0 V (ground) or ~12 V depending on vehicle design — check vehicle wiring: some switches pull the input to ground when closed, others to battery voltage
- When brake pedal actuated the input should change state (toggle between low and high).
- Expected voltage change should be rapid and stable with pedal travel; intermittent or floating voltages indicate wiring/switch faults
- No high resistance (>1–2 ohm under mechanical connectors aside) between switch and module for power/ground circuits
Diagnostic algorithm
- Retrieve freeze frame and note ignition key state, battery voltage, and related codes. Check for multiple brake-switch related codes.
- Perform visual inspection of switch, harness, and connectors at the brake pedal and module. Repair obvious damage.
- With key ON (engine off) observe live data for Brake Switch B status. Press and release pedal — note expected status change and compare to Brake Switch A if present.
- Backprobe the switch connector. With multimeter measure voltage on the switch signal lead relative to ground with pedal released and pressed. Verify expected low/high transition.
- If the signal is high when it should be low, disconnect the brake switch. Measure voltage at the module input pin with the switch disconnected; if still high, suspect short to battery or module fault.
- Check continuity between switch signal pin and module input pin. Check for short to battery (voltage present when circuit should be open) or short to ground when it should be high.
- Inspect and test related fuses and grounds. Wiggle test harness while monitoring signal for intermittent faults.
- If wiring and connectors check good, substitute or bench-test a known-good brake switch. Replace switch if it fixes the fault.
- If replacement switch does not clear the issue, test/replace the receiving control module input or repair short in harness. Consult wiring diagrams and module pinouts before module replacement.
- Clear codes, perform functional tests and road test to confirm repair. Re-scan for codes and monitor live data again.
Likely causes
- Defective brake switch (most common)
- Connector pin pushed out/corroded at brake switch or module
- Short to battery voltage in harness near pedal or junction
- Intermittent open/short in harness due to rubbing/chafing
Fault status
Status
Brake Switch B Circuit High — control module detects higher-than-expected voltage on the Brake Switch B input. Check switch, wiring, connectors, and module input for short-to-voltage or faulty switch.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P0724
MERCEDES-BENZ
P — Powertrain
Torque Converter/Brake Switch B Circuit High
Views:
UK: 15
EN: 15
RU: 14
AI status
Completed
Completed
100%
Causes
- Failed or misadjusted brake light / brake pedal switch (Brake Switch B)
- Open or shorted wiring (short to battery/ignition voltage) on the switch circuit
- Corroded, loose, or damaged connector/pins at switch or control module
- Faulty body control module (BCM), engine control module (ECM) or transmission control module (TCM) input circuit
- Blown fuse or poor ground elsewhere causing unusual voltage on the circuit
- Aftermarket wiring or tapped circuits creating backfeed
Symptoms
- Brake lights may be stuck on or off, or behave intermittently
- Cruise control disabled or will not engage
- ABS/ESC or traction control warnings may illuminate
- Gear shift interlock or start/stop related issues (cannot shift out of park or engine won't start in some vehicles)
- Erratic transmission torque converter lockup or shift behavior (if input used by TCM)
What to check
- Read and record freeze frame and live data with a scan tool (brake switch B status/voltage)
- Visually inspect brake switch, connector, and wiring for damage, corrosion, or disconnection
- Operate brake pedal while observing switch operation and brake lights
- Backprobe the switch connector and measure voltage/logic signal with a multimeter
- Check continuity between switch and control module input pin, and for shorts to battery
- Verify proper ground(s) related to the switch and module
Signal parameters
- Typical idle (switch open) voltage: ~0 V (ground) or ~12 V depending on vehicle design — check vehicle wiring: some switches pull the input to ground when closed, others to battery voltage
- When brake pedal actuated the input should change state (toggle between low and high).
- Expected voltage change should be rapid and stable with pedal travel; intermittent or floating voltages indicate wiring/switch faults
- No high resistance (>1–2 ohm under mechanical connectors aside) between switch and module for power/ground circuits
Diagnostic algorithm
- Retrieve freeze frame and note ignition key state, battery voltage, and related codes. Check for multiple brake-switch related codes.
- Perform visual inspection of switch, harness, and connectors at the brake pedal and module. Repair obvious damage.
- With key ON (engine off) observe live data for Brake Switch B status. Press and release pedal — note expected status change and compare to Brake Switch A if present.
- Backprobe the switch connector. With multimeter measure voltage on the switch signal lead relative to ground with pedal released and pressed. Verify expected low/high transition.
- If the signal is high when it should be low, disconnect the brake switch. Measure voltage at the module input pin with the switch disconnected; if still high, suspect short to battery or module fault.
- Check continuity between switch signal pin and module input pin. Check for short to battery (voltage present when circuit should be open) or short to ground when it should be high.
- Inspect and test related fuses and grounds. Wiggle test harness while monitoring signal for intermittent faults.
- If wiring and connectors check good, substitute or bench-test a known-good brake switch. Replace switch if it fixes the fault.
- If replacement switch does not clear the issue, test/replace the receiving control module input or repair short in harness. Consult wiring diagrams and module pinouts before module replacement.
- Clear codes, perform functional tests and road test to confirm repair. Re-scan for codes and monitor live data again.
Likely causes
- Defective brake switch (most common)
- Connector pin pushed out/corroded at brake switch or module
- Short to battery voltage in harness near pedal or junction
- Intermittent open/short in harness due to rubbing/chafing
Fault status
Status
Brake Switch B Circuit High — control module detects higher-than-expected voltage on the Brake Switch B input. Check switch, wiring, connectors, and module input for short-to-voltage or faulty switch.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Was this AI description helpful?
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