Diagnostic Test

CHECK FOR AN ACTIVE DTC
NOTE:
This DTC must be active for the results of this test to be valid.
1. Perform any Service Bulletins that may apply.
2. Turn the ignition on.
3. With the scan tool, read ABS DTCs and record on the repair order.
4. With the scan tool, read and record Environmental Data to help identify the conditions in which the DTC was set.
5. With the scan tool, erase ABS DTCs.
6. Turn the ignition off.
7. Start the Vehicle.
8. Press the brake pedal firmly and release.
9. With the scan tool, read ABS DTCs.
  Is the DTC active??
  
  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 .
CHECK FOR BRAKE PEDAL POSITION (BPP) SENSOR CIRCUIT RELATED DTCS
1. Refer to the recorded DTCs.
  Are there any BPP Sensor circuit related DTCs active?
  
  Yes
  - Perform the appropriate diagnostic procedures before continuing with this test. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
  No
  - Go To 3
PERFORM THE BRAKE PEDAL CALIBRATION ROUTINE
1. Park the vehicle on level ground.
  NOTE:
  When performing the Brake Pedal Sensor routine(s), make sure the brake pedal is NOT pressed.
2. With the scan tool under ABS in the "Miscellaneous Functions" menu, perform the Brake Pedal Calibration routine.
  NOTE:
  This step only applies to applicable vehicles.
3. With the scan tool under PCM in the "Miscellaneous Functions" menu, perform the Brake Pedal Learn routine (if available).
  Were the Brake Pedal routine(s) successful?
  
  Yes
  - Test complete.
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Perform the Brake Pedal Calibration routine(s) again, if still unsuccessful.
  - Go To 4
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.
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Go To 5
CHECK THE BRAKE PEDAL POSITION (BPP) SENSOR FOR PROPER OPERATION
1. Turn the ignition off.
2. Disconnect the BPP Sensor harness connector.
3. Turn the ignition on.
1. Measure the voltage at the BPP Sensor harness connector between the (B237) BPP Sensor Feed and the (B937) BPP Sensor Return.
  Is the voltage above 4.75 volts?
  
  Yes
  - Replace the Brake Pedal Position (BPP) Sensor in accordance with the Service Information. Refer to SENSOR, STOP LAMP, REMOVAL AND INSTALLATION .
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Go To 6
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 ABS VERIFICATION TEST. Refer to MODULE, ANTI-LOCK BRAKE SYSTEM (ABS), REMOVAL AND INSTALLATION .
  No
  - Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  - Test complete.