Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, read ABS DTCs and record on the vehicle 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. Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
6. With the scan tool, read ABS DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
  - Perform the ABS-INTERMITTENT CONDITION TEST. Refer to ABS INTERMITTENT CONDITION .
BRAKE PEDAL POSITION (BPP) SENSOR NOT APPLIED VOLTAGE
1. Start the engine.
2. With the scan tool, under "Data Display" monitor the BPP voltage and Stoplamp Switch while pressing the brake pedal slowly.
  Does the voltage increase and the stoplamp switch status change when the BPP voltage changes by 0.85 volts while the brake pedal is being applied?
  
  Yes
  - Perform the ABS-INTERMITTENT CONDITION TEST. Refer to ABS INTERMITTENT CONDITION .
  No
  - Go To 3
INSPECT THE BRAKE PEDAL POSITION (BPP) SENSOR FOR INCORRECT INSTALLATION, DAMAGE OR MECHANICAL FAILURE
1. Turn the ignition off.
2. Visually inspect the BPP Sensor for Improper installation, damage or mechanical failure. Refer to SENSOR, STOP LAMP, REMOVAL AND INSTALLATION .
  Were any problems found?
  
  Yes
  - Repair as necessary and perform the "Brake Pedal Sensor Calibration" routine.
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Go To 4
PERFORM THE BRAKE PEDAL POSITION (BPP) SENSOR CALIBRATION ROUTINE
1. Turn the ignition on.
2. With the scan tool, under "Miscellaneous Functions" perform the Brake Pedal Sensor Calibration routine.
3. With the scan tool, erase the DTCs.
4. Cycle the ignition from of to on.
5. With the scan tool, read the DTCs.
  Did the DTC return?
  
  Yes
  - Perform the Brake Pedal Sensor Calibration routine again, if still unsuccessful.
  - Go To 5
  No
  - Test complete.
REPLACE THE BRAKE PEDAL POSITION (BPP) SENSOR AND TEST FOR DTCS
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.
  Did the DTC return?
  
  Yes
  - Go To 6
  No
  - Test complete.
CHECK RELATED HARNESS CONNECTIONS
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.