Faulty Signal

Faulty signal

Checking the operation of the pump motor








- Ignition off
- Check the brake control module (BCM) and pump motor connectors. Check for contact resistance and oxidation
- Reconnect the components, connectors etc.
- Ignition on
- Activate the pump motor.
Check that the pump motor starts and operates normally.
If the pump motor starts and seems to operate normally, the cause of the fault was probably contact resistance and oxidation in the control module or pump motor connectors.

Other information
- To disconnect the control module and pump motor, see Connecting the breakout box, brake control module (BCM) Connecting the Breakout Box, Brake Control Module (BCM)
- Checking wiring and terminals Checking Wiring And Terminals





Is the pump OK?

Yes - Fault Found

No - Checking the wiring and component

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

Checking the wiring and component




- Ignition off.
Check the circuit for the pump motor between brake control module (BCM) terminal #1 (#A1) and the fuse in the integrated relay/fusebox in the engine compartment. Check for an open-circuit. Check for a short-circuit to ground.
Check the fuse for the brake system in the integrated relay / fusebox in the engine compartment. If the fuse is blown, check the cable between the fuse and control module terminal #1 (#A1). Check for a short-circuit to ground. Then replace the fuse.
Remedy as necessary.

Other information
- To connect the breakout box, see Connecting the breakout box, brake control module (BCM) Connecting the Breakout Box, Brake Control Module (BCM)
- Checking wiring and terminals Checking Wiring And Terminals
- For further information about the fuses and relays, see the Wiring Diagram.









Was a fault detected?

Yes - Verification

No - Checking the pump motor circuit

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

Checking the pump motor circuit




- Ignition off
- Remove the brake control module (BCM)
- Connect adapter 951 2856 Test cable 951 2856 Test Cable to the power supply terminal on the pump motor
- Connect the red fused cable to battery voltage. The black cable must be connected to ground.
The pump motor must start when the cable is connected. Run for a maximum of 10 seconds.
Replace the control module if the pump motor starts and seems to run normally.
Replace the hydraulic unit if the pump motor does not start.

Other information
- To replace the control module, see Brake Control Module (BCM), replacing Brake Control Module (BCM), Replacing
- To replace the hydraulic unit, see Hydraulic unit, replacing Service and Repair.






Continue - Verification

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

Verification




Verification

Verification

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








- Ignition off
- Reconnect the components, connectors etc.
- Ignition on
- Activate the pump motor.
Check that the pump motor starts and operates normally.





Is the pump 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 - FAULT-TRACING FAILED

No - Attempt New Test

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

FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the operation of the pump motor

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