Faulty Signal

Faulty signal

Checking the status




- Ignition on.
Activate the read off for the signals for the brake pedal position sensor and stop lamp switch.
Check that the value at the brake pedal position sensor is approximately 7% when the brake pedal is unaffected and approximately 80% when the pedal is fully depressed with the engine running. Check also that the stop lamp switch changes status. When the brake pedal is unaffected, "OFF" must be displayed. If the brake pedal is depressed slightly, the status must change to "ON".

Note! If an incorrect value is obtained from the brake pedal position sensor, the brake control module (BCM) must initially be searched for the fault cause.

The fault is intermittent at present if the values and the status from the brake pedal position sensor and the stop lamp switch correspond as above.






Continue - Checking the power supply

-------------------------------------------------

Checking the power supply




- Ignition on.
Check the power supply to the stop lamp switch. Take readings between stop lamp switch terminal #2 (cable harness side) and the ground terminal. The power supply must be approximately 12 V.

If there is no power supply:
Check the power supply circuit for stop lamp switch terminal #2 (cable harness side). Check for an open-circuit. Check for a short-circuit to ground. Check for a blown fuse in the circuit.
Remedy as necessary.

Other information
- Connecting the breakout box Connecting The Breakout Box, Engine Control Module (ECM)
- Signal specification Signal Specification, Engine Control Module (ECM)
- For further information about the fuses and relays, see the Wiring Diagram
- Stoplamp switch Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals














Continue - Checking the component and wiring

-------------------------------------------------

Checking the component and wiring




- Ignition off
- Check that the stop lamp switch is correctly installed.
Check the resistance of the stop lamp switch with the switch pressed in and with the switch released. Take readings between terminals #1 and #2 (component side) on the stop lamp switch.

Hint: The stop lamp switch must be closed when the brake pedal is depressed. The resistance of the stop lamp switch must be infinite when the brake pedal is unaffected.

Check the stop lamp switch and engine control module (ECM) connectors. Check for contact resistance. Check for oxidation.
Check the cable between stop lamp switch terminal #1 (cable harness side) and engine control module (ECM) terminal #B41 (#C41). Check for loose connections. Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
Remedy as necessary.

Other information
- Connecting the breakout box Connecting The Breakout Box, Engine Control Module (ECM)
- Signal specification Signal Specification, Engine Control Module (ECM)
- Stoplamp switch Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals














Continue - Verification

-------------------------------------------------

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.
Activate the read off for the signals for the brake pedal position sensor and stop lamp switch.
Check that the value for brake position sensor at unaffected brake pedal is approx. 7% and when the pedal is fully pressed down approx. 80% when the engine is running. Also check that the brake light switch changes status. The status must be OFF with the brake pedal unaffected and change to ON when the brake pedal is pressed.
If values and status from the brake position sensor and brake light switch do not match acc. to the above, this indicates incorrect function.





Is the function OK?

Yes - VERIFIED

No - VERIFICATION FAILED

------------------------

VERIFIED - Fault Found

VERIFICATION FAILED - Fault-tracing information

-------------------------------------------------

Fault-tracing 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

------------------------

Attempt New Test - Checking the status

-------------------------------------------------