Troubleshooting
Troubleshooting BCM-C004864
Checking diagnostic trouble codes in CEM and ECM
If there are any diagnostic trouble codes for the brake pedal position sensor or the brake light switch stored in the engine control module (ECM) or in the central electronic module (CEM), perform troubleshooting of these first.
Were any diagnostic trouble codes stored for the pedal position sensor or brake light switch?
Yes - DONE
No - Checking control module and the sensor's connector
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Checking control module and the sensor's connector
Hint: The cause of the diagnostic trouble code can be found in the circuit for the brake light switch or the pedal position sensor.
- Ignition off
- Check the connectors of the brake control module (BCM), brake light switch, and the pedal position sensor for contact resistance and oxidation.
- Reinstall the components, reconnect the connectors etc.
- Ignition on
- Read off the status of the brake light switch and the pedal position sensor's position.
Depress the brake pedal and let it up again. The value shall change between OFF and ON, and the pedal position sensor's position shall be updated.
Other information
- Connecting the breakout box, brake control module (BCM), B6324S5 Connecting The Breakout Box
- Stop lamp switch, replacing Service and Repair
- Pedal sensor power brake booster, replacing Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals
Select an alternative:
1. The value for the brake light switch does not change.
2. The value for the pedal position sensor is not updated.
3. The values are OK.
Select an alternative.
1 - Checking fuses, wiring and sensors
2 -
3 - No Fault Found
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Checking fuses, wiring and sensors
Check that the fuse for the brake light circuit is okay. If the fuse is damaged, first check the circuit to the brake light switch for short-circuiting to voltage before the replacing the fuse.
If the fuse is okay, check the circuit for the brake light switch for open circuit and short-circuit to ground.
Remedy as necessary.
Other information
- Connecting the breakout box, brake control module (BCM), B6324S5 Connecting The Breakout Box
- To connect the breakout box to the Engine control module (ECM), see: Connecting the breakout box, B6324S5 Connecting The Breakout Box, Engine Control Module (ECM)
- For connecting breakout box to Central Electronic Module (CEM): Connecting the breakout box Connecting The Breakout Box, Central Electronic Module (CEM)
- Stop lamp switch, replacing Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals
Was a malfunction detected?
Yes - Verification
No - No Fault Found
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Signal outside permitted range
Checking the connectors
- Ignition off
- Check the connectors of the brake control module (BCM) and the pedal position sensor for contact resistance and oxidation.
- Reinstall the components, reconnect the connectors etc.
- Connect a breakout box.
- Ignition on
- Read off the pedal position sensor signal.
Press down the brake pedal and check that the pedal's signals are updated.
Other information
- Checking wiring and terminals Checking Wiring And Terminals.
Were the signals updated?
Yes - FAULT FOUND
No - Checking wiring and sensors
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Checking wiring and sensors
Check the cables between:
- pedal position sensor terminal #1 and brake control module (BCM) terminal #7 (#A7)
- pedal position sensor terminal #2 and brake control module (BCM) terminal #5 (#A5)
- pedal position sensor terminal #3 and brake control module (BCM) terminal #3 (#A3)
check for open circuit, short-circuit to ground and short-circuit to voltage.
Hint: Connect an ohmmeter between #2 and #3 on the pedal position sensor's connector.
The resistance shall be approx. 0.5 kohms with the brake pedal inactivated and approx. 2.5-3 kohms with depressed brake pedal.
Connect the ohmmeter between #1 and #3 on the pedal position sensor's connector.
The resistance shall be approx. 2.5-3 kohms with the brake pedal inactivated and approx. 0.5 kohms with depressed brake pedal.
If resistance is incorrect, replace the pedal position sensor.
If no defect is found, replace the pedal position sensor.
Other information
- Pedal sensor power brake booster, replacing Service and Repair
- Signal specification, brake control module (BCM) with DSTC (dynamic stability and traction control), B6324S5 Signal Specification, Brake Control Module (BCM) With DSTC (Dynamic Stability And Traction Control).
- Checking wiring and terminals Checking Wiring And Terminals
Continue - Verification
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Verification
Hint: After carrying out the repair, check that the malfunction has been remedied.
- Ignition off
- Reinstall the components, reconnect the connectors etc.
- Ignition on
- Read off the pedal position sensor signal.
Press down the brake pedal and check that the pedal's signals are updated.
Were the signals updated?
Yes - FAULT FOUND
No - Troubleshooting information
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Troubleshooting information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking the connectors
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DONE - DONE
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Verification
Verification
Hint: After carrying out the repair, check that the malfunction has been remedied.
- Ignition off
- Reconnect the connectors, components, etc.
- Ignition on
- Read the status of the brake light switch.
Depress the brake pedal and release it. The value should change between OFF and ON.
Does the value change?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFIED - FAULT FOUND
VERIFICATION FAILED - Troubleshooting information
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Troubleshooting information
Attempt New Test - Checking diagnostic trouble codes in CEM and ECM
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