Diagnostic Test

1. Turn the ignition on.
2. With the scan tool, read ABS DTCs and record on the repair order.
3. With the scan tool, read and record the Environmental Data to help identify the conditions in which the DTC was set.
4. With the scan tool, erase the DTCs.
5. Start the engine.
6. Press and release the brake pedal.
7. With the scan tool, read ABS DTCs.

   Is the DTC active?

   Yes 

   • Go To  2

   No 

   • Perform the ABS-INTERMITTENT CONDITION TEST. Refer to ABS INTERMITTENT CONDITION .

1. Refer to the recorded DTCs.

   Are there any other BPP Sensor related DTCs active?

   Yes 

   • Perform the applicable diagnostic procedure(s). Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .

   No 

   • Go To  3

1. Turn the ignition off.
2. Disconnect the Body Control Module (BCM) C4 harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Disconnect the Anti-lock Brake System (ABS) Module harness connector.
4. Turn the ignition on.
5. Using a DVOM, measure the voltage of the circuit being tested at the ABS Module harness connector.

Is there any voltage present?

Yes 

• Repair the (B15) Brake Signal circuit for a short to voltage.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

No 

• Go To  4

1. The ignition must be off when checking the continuity of a circuit.
2. Disconnect the Anti-lock Brake System (ABS) Module harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Disconnect the Body Control Module (BCM) C4/D harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
4. Using a DVOM, check the continuity of the circuit being tested at the ABS Module harness connector and check for continuity between the circuit and ground.

Is there continuity between ground and the (B15) Brake Signal 1 circuit?

Yes 

• Repair the (B15) Brake Signal 1 circuit for a short to ground.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

No 

• Go To  5

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the ABS Module harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Isolate the circuit by disconnecting the BCM C4/D harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
4. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
5. Connect one lead of the DVOM to the circuit being tested at the ABS Module harness connector.
6. Connect the other lead to the circuit being tested at the Body Control Module (BCM) harness connector and measure the resistance of the circuit.

1. Measure the resistance of the (B15) Brake Signal 1 circuit between the BCM harness connector and the ABS Module harness connector.

   Is the resistance below 3.0 Ohms?

   Yes 

   • Go To  6

   No 

   • Repair the (B15) Brake Signal 1 circuit for an open or high resistance.
   • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

1. Replace the Brake Pedal Position (BPP) Sensor in accordance with the Service Information. Refer to SENSOR, STOP LAMP, REMOVAL AND INSTALLATION .
2. Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
   WARNING:

   To avoid possible serious or fatal injury, check brake capability is available before road testing.

3. Test drive the vehicle on mainly straight road conditions at a velocity above 20 km/h (12 mph).
4. With the scan tool, read the DTCs.

   Does the DTC remain active?

   Yes 

   • Go To  7

   No 

   • Test complete.

1. Disconnect the ABS Module harness connector.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
   • Proper connector installation.
   • Damaged connector locks.
   • Corrosion.
   • Other signs of water intrusion.
   • Weather seal damage (if equipped).
   • Bent terminals.
   • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
   • Terminals that have been pushed back into the connector cavity.
   • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

   Repair any conditions that are found.

5. Connect the ABS Module harness connector. Be certain that the harness connector is fully seated and the connector lock is fully engaged.
6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Connect the related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
   WARNING:

   To avoid possible serious or fatal injury, check brake capability is available before road testing.

9. Using the recorded Event and Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read ABS Module DTCs.

    Did the DTC return?

    Yes 

    • Replace the Anti-lock Brake System (ABS) Module in accordance with the Service Information. Refer to MODULE, ANTI-LOCK BRAKE SYSTEM (ABS), REMOVAL AND INSTALLATION .
    • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

    No 

    • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
    • Test complete.