FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Faulty Signal






Faulty signal

Checking the connectors








- Ignition off
- Check the connectors for the brake control module (BCM), pedal position sensor and brake pressure sensor. Check for contact resistance and oxidation
- Reinstall the components, reconnect the connectors etc.
- Ignition on.
Test drive the car. See Test Drive Form (DSTC (dynamic stability and traction control) /brake control module), description Test Drive Form (DSTC (Dynamic Stability And Traction Control) /Brake Control Module), Description.
Read off the status of the diagnostic trouble code (DTC).

Other information
- To connect the breakout box, see Connecting the breakout box, brake control module (BCM) Connecting the Breakout Box, Brake Control Module (BCM)
- To disconnect the pedal position sensor connector, see Pedal sensor power brake booster, replacing Service and Repair
- To disconnect the connectors for the brake pressure sensors, see Pressure sensor, master cylinder, replacing Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals





Is the status of the diagnostic trouble code (DTC) intermittent?

Yes - Fault Found

No - Checking the wiring and component

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Checking the wiring and component
Check the wiring between pedal position sensor
- terminal #1 and brake control module (BCM) terminal #7 (#A7)
- terminal #2 and brake control module (BCM) terminal #5 (#A5)
- terminal #3 and brake control module (BCM) terminal #3 (#A3).
check for an open-circuit, a short-circuit to ground and a short-circuit to supply voltage.
Check the pedal position sensor as follows
- ignition off
- connect the breakout box to the wiring
- the control module disconnected.
measure the resistance at the pedal position sensor.
The resistance between terminals #3 (#A3) and #5 (#A5) must be approximately 0.5 kohms when the brake pedal is unaffected. The resistance must increase when the brake pedal is pressed.
The resistance between terminals #3 (#A3) and #7 (#A7) must be approximately 2.5 kohms when the brake pedal is unaffected. The resistance must decrease when the brake pedal is pressed.
Replace the pedal position sensor if the resistance is incorrect.
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)
- To replace the pedal position sensor, see Pedal sensor power brake booster, replacing Service and Repair
- For information about signals, see Signal specification, brake control module (BCM) with DSTC (dynamic stability and traction control) Signal Specification.









Was a fault detected?

Yes - Verification

No - Checking wiring and sensors

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Checking wiring and sensors
Check the wiring between the control module and the connectors for the brake pressure sensors.

For brake pressure sensor 1:
- terminal #1 and control module terminal #19 (terminal #A19)
- terminal #2 and control module terminal #20 (#A20)
- terminal #3 and control module terminal #18 (#A18).

For brake pressure sensor 2:
- terminal #1 and control module terminal #21 (#A21)
- terminal #2 and control module terminal #23 (terminal #A23)
- terminal #3 and control module terminal #22 (terminal #A22).
check for an open-circuit, a short-circuit to ground and a short-circuit to supply voltage.

Hint: Check the brake pressure sensors. First connect the breakout box and the connectors for the sensors. Switch on the ignition. Measure the signal from the sensor:

Brake pressure sensor 1:
- terminal #A19 and terminal #A20 on the breakout box. The voltage must be between approximately 0.25- 4.75 V, depending on the brake pressure
- terminal #A18 and terminal #A19 on the breakout box. The voltage must be approximately 5 V.

Brake pressure sensor 2:
- terminal #A21 and terminal #A23 on the breakout box. The voltage must be between approximately 0.25- 4.75 V, depending on the brake pressure
- terminal #A21 and terminal #A22 on the breakout box. The voltage must be approximately 5 V.

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)
- To replace brake pressure sensors 1 and 2, see Pressure sensor, master cylinder, replacing Service and Repair
- For information about signals, see Signal specification, brake control module (BCM) with DSTC (dynamic stability and traction control) Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals









Was a fault detected?

Yes - Verification

No - Fault Tracing Information

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Verification




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








- Ignition off
- Reconnect the connectors, reinstall components etc.
- Test drive the car. See Test Drive Form (DSTC (dynamic stability and traction control) /brake control module), description Test Drive Form (DSTC (Dynamic Stability And Traction Control) /Brake Control Module), Description
- Ignition on.
Read off the status of the diagnostic trouble code (DTC).





Is the status of the diagnostic trouble code (DTC) intermittent?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - Fault Found

VERIFICATION FAILED - Fault-tracing information

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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

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the connectors

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Information

Fault-tracing information
The fault should be diagnosed and remedied. Since this is not the case the fault-tracing process has failed.
Complete the fault-tracing for those fault or try again.

Do you want to terminate fault-tracing at this time?

Yes - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the connectors

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