Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
2. Record the Environmental Data and any DTCs.
3. With the scan tool, erase DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. With the scan tool, read BCM DTCs.
  Did the DTC return?
  
  Yes
  - Go to 2
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer TESTING FOR AN INTERMITTENT CONDITION to STANDARD PROCEDURE .
CHECK FOR DTCS IN THE ANTI-LOCK BRAKE SYSTEM (ABS) MODULE
1. With the scan tool, read ABS Module DTCs.
  Are there any DTCs set in the ABS Module?
  
  Yes
  - Perform the appropriate diagnostic test. Refer to DIAGNOSIS AND TESTING .
  No
  - Go To 3
CHECK FOR VOLTAGE ON THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT
1. Turn the ignition off.
2. Disconnect the Brake Fluid Level Switch harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (B20) Brake Fluid Level Signal circuit at the Brake Fluid Level Switch harness connector.
  Is the voltage greater than 5.0 volts?
  
  Yes
  - Go To 4
  No
  - Go To 5
CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the ABS Module C1 harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (B20) Brake Fluid Level Signal circuit at the Brake Fluid Level Switch harness connector.
  Is the voltage greater than 5.0 volts?
  
  Yes
  - Repair the short to voltage in the (B20) Brake Fluid Level Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 8
CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the ABS Module C1 harness connector.
3. Measure the resistance of the (B20) Brake Fluid Level Signal circuit between the Brake Fluid Level Switch harness connector and the ABS Module C1 harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (B20) Brake Fluid Level Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 6
CHECK THE (Z912) GROUND CIRCUIT FOR AN OPEN
1. Measure the resistance of the (Z912) Ground circuit between ground and the Brake Fluid Level Switch harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (Z912) Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 7
CHECK THE ABS MODULE FOR CORRECT OPERATION
1. Connect the ABS Module C1 harness connector.
2. Connect a jumper wire between the (B20) Brake Fluid Level Signal circuit and the (Z912) Ground circuit at the Brake Fluid Level Switch harness connector.
3. Turn the ignition on.
4. With the scan tool, read the Brake Fluid Level data.
  Does the Brake Fluid Level display Low Level?
  
  Yes
  - Replace the Brake Fluid Level Switch in accordance with the Service Information. Refer to SWITCH, BRAKE FLUID LEVEL, REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 9
CHECK RELATED ABS MODULE HARNESS CONNECTIONS
1. Disconnect all ABS Module harness connectors.
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. Reconnect all ABS Module harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all 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.
9. Using the recorded 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 BCM 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 BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.
CHECK RELATED BCM HARNESS CONNECTIONS
1. Disconnect all BCM harness connectors.
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. Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all 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.
9. Using the recorded 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 BCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.