Incorrect Signal

Incorrect signal

Checking diagnostic trouble codes (DTCs)
Check if any diagnostic trouble codes are stored in the brake control module (BCM) or in the central electronic module (CEM).
If diagnostic trouble codes are stored in the brake control module (BCM) or in the central electronic module (CEM), these shall be taken care of first.

Have fault causes been searched for or remedied in the above control modules?

Yes - Checking the status

No - DONE

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Checking the status




- Ignition on
- Read off the status from the brake light switch.
Check the function of the brake light switch by slowly pressing down and letting up the brake pedal.
Check that the status changes between "OFF" when brake pedal is not pressed and "ON" when brake pedal is pressed.
If the status from the brake light switch changes according to the above when pressing on the brake pedal, this indicates that the malfunction is intermittent at this time.






Continue - Checking voltage feed

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Checking voltage feed




- Ignition on
Check voltage feed to the brake light switch. Measure between the brake light switch #1 (against cable harness) and ground (frame grounding point). Voltage feed shall be approx. 12 V.

If voltage feed is missing:
Check the circuit for voltage feed to the brake light switch #1 (against cable harness) for open circuit, short-circuit to ground and damaged fuse for the circuit.
Remedy as necessary.

Other information:
- Checking wiring and terminals Checking Wiring And Terminals.
- For information about the fuses and relays, see wiring diagram.
- To connect the breakout box, see Connecting the breakout box, B5244T5, B5254T2 Connecting the Breakout Box.
- For information on signals 5-cyl, see Signal specification Signal Description / Specification.
- For information on signals 6-cyl, see Signal specification Signal Description / Specification.
- To access/replace brake light switch, see Stop lamp switch, replacing Service and Repair.










Continue - Checking components and wiring

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Checking components and wiring




- Ignition off
- Check that the brake light switch is installed correctly and adjusted.
Check the connectors for the brake light switch and engine control module (ECM) for contact resistance or oxidation and for damage to pins and connections.
Check the connectors and terminals for water penetration.
Check the cable between the brake light switch #5 (against cable harness) and engine control module (ECM) #B26 (#B36) for open circuit or short-circuit to ground or short-circuit to voltage.
Check connector B for central electronic module (CEM) for contact resistance or oxidation.
Check the cable between the brake light switch #5 (against cable harness) and central electronic module (CEM) #4B for open circuit, short-circuit to ground or short-circuit to voltage.
Remedy as necessary.

Other information:
- Checking wiring and terminals Checking Wiring And Terminals.
- For information about cable routing and connections, see wiring diagram.
- For resistance value, see Component specifications Specifications.
- To connect the breakout box, see Connecting the breakout box, B5244T5, B5254T2 Connecting the Breakout Box.
- For information on signals 5-cyl, see Signal specification Signal Description / Specification.
- For information on signals 6-cyl, see Signal specification Signal Description / Specification.
- Checking brake light switch adjustment: Checking brake light switch adjustment Testing and Inspection.
- To access/replace central electronic module (CEM), see Central electronic module (CEM), replacing Central Electronic Module (CEM), Replacing.










Continue - Verification

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Verification




Verification

Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off
- Reconnect the connectors, reinstall components etc.
- Ignition on
- Read off the status from the stop lamp switch.
Check the function of the stop lamp switch by carefully pressing and releasing the brake pedal.
Check that the status changes between "OFF" when the brake pedal is unaffected and "ON" when the brake pedal is depressed.
If the status of the stop lamp switch changes as described above when the brake pedal is depressed, the fault has been remedied.





Is the function OK?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - Fault Found

VERIFICATION FAILED - 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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking diagnostic trouble codes (DTCs)

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