Diagnostic Test

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 .

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the ABS Module harness connector and the Vacuum Pressure Sensor harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. 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.
4. Connect one lead of the DVOM to the circuit being tested at the Vacuum Pressure Sensor harness connector.
5. Connect the other lead to the circuit being tested at the ABS Module harness connector and measure the resistance of the circuit.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  3

No 

• Repair the circuit for an open/high resistance.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

1. Turn the ignition off.
2. Isolate the circuit by disconnecting the ABS Module harness connector and the Vacuum Pressure Sensor harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Turn the ignition on.
4. Using a DVOM, measure the voltage of the circuit being tested at the component harness connector.

Is there any voltage present?

Yes 

• Repair the circuit for a short to voltage. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

No 

• Go To  4

1. The ignition must be off when checking a circuit for continuity to ground.
2. Isolate the circuit by disconnecting the ABS Module harness connector and the Vacuum Pressure Sensor harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect the negative lead of the DVOM to a known good ground.
4. With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.

Is there continuity between ground and the circuit being tested?

Yes 

• Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
• Perform 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 and the Vacuum Pressure Sensor harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. 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.
4. Connect one lead of the DVOM to the circuit being tested at the Vacuum Pressure Sensor harness connector.
5. Connect the other lead to the circuit being tested at the ABS Module harness connector and measure the resistance of the circuit.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  6

No 

• Repair the circuit for an open/high resistance.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the ABS Module harness connector and the Vacuum Pressure Sensor harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. 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.
4. Connect one lead of the DVOM to the circuit being tested at the Vacuum Pressure Sensor harness connector.
5. Connect the other lead to the circuit being tested at the ABS Module harness connector and measure the resistance of the circuit.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  7

No 

• Repair the circuit for an open/high resistance.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

1. The ignition must be off when checking for a short between circuits.
2. Isolate the circuit by disconnecting the ABS Module harness connector and the Vacuum Pressure Sensor harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect the test leads of the DVOM and check for continuity between the circuits being tested at the component harness connector.

Is there continuity between the circuits?

Yes 

• Repair the short between the circuits. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

No 

• Go To  8

1. The ignition must be off when checking for a short between circuits.
2. Isolate the circuit by disconnecting the ABS Module harness connector and the Vacuum Pressure Sensor harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect the test leads of the DVOM and check for continuity between the circuits being tested at the component harness connector.

Is there continuity between the circuits?

Yes 

• Repair the short between the circuits. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
• Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

No 

• Go To  9

1. Replace the Vacuum Pressure Sensor.
2. Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
3. Turn the ignition on.
4. With the scan tool, read the DTCs.

   Did the DTC return?

   Yes 

   • Go To  10

   No 

   • Test complete.

1. Turn the ignition off.
2. Disconnect the ABS Module harness connector.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. 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.

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

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

10. 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.
11. 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 ABS VERIFICATION TEST .

    No 

    • The wiring or poor connection problem has been repaired.
    • Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .