Diagnostic Test

CHECK FOR AN ACTIVE DTC
NOTE:
When the Brake Pedal is at rest (not applied) the internal switch state for Brake Signal 1 is normally closed (N.C.) and the internal switch state for Brake Signal 2 is normally open (N.O.). When the Brake Pedal is depressed (applied) both internal switches will change to the opposite states.
1. With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
2. Record the Environmental Data.
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 INTERMITTENT CONDITIONS procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK FOR ADDITIONAL STOP LAMP SWITCH DTCS
1. With the scan tool, read the DTCs from all modules.
  Are there any other Stop Lamp Switch related DTCs Active?
  
  Yes
  - Perform the appropriate Stop Lamp Switch related diagnostic procedure before proceeding with this diagnostic test.
  No
  - Go To 3
CHECK THE (F102) IGNITION RUN-START CONTROL OUTPUT CIRCUIT FOR AN OPEN OR SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the Stop Lamp Switch C1 harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (F102) Ignition Run-Start Control Output circuit at the Stop Lamp Switch C1 harness connector.
  Is the voltage above 9.0 volts?
  
  Yes
  - Go To 4
  No
  - Check for an open F53 Fuse. If no problems are found, repair the open in the (F102) Ignition Run-Start Control Output circuit. If the fuse is open, inspect for a short to ground in the (F102) Ignition Run-Start Control Output circuit and repair, if needed.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (B15) BRAKE SIGNAL 1 AND (B16) BRAKE SIGNAL 2 CIRCUITS FOR A SHORT TO VOLTAGE
1. Measure the voltage on the (B15) Brake Signal 1 circuit at the Stop Lamp Switch C1 harness connector.
2. Measure the voltage on the (B16) Brake Signal 2 circuit at the Stop Lamp Switch C1 harness connector.
  Is there any voltage present at any of the connections?
  
  Yes
  - Repair the short to voltage in the (B15) Brake Signal 1 or (B16) Brake Signal 2 circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
CHECK THE STOP LAMP SWITCH FOR PROPER OPERATION
1. Turn the ignition off.
2. Perform the DIAGNOSIS AND TESTING - STOP LAMP SWITCH procedure in accordance with the Service Information. Refer to SWITCH, STOP LAMP, DIAGNOSIS AND TESTING .
  Does the Stop Lamp Switch operate correctly?
  
  Yes
  - Go To 6
  No
  - Replace the Stop Lamp Switch in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (B15) BRAKE SIGNAL 1 AND (B16) BRAKE SIGNAL 2 CIRCUITS FOR A SHORT TO GROUND
1. Disconnect the BCM C4/D harness connector.
2. Check for continuity between ground and the (B15) Brake Signal 1 circuit at the BCM C4/D harness connector.
3. Check for continuity between ground and the (B16) Brake Signal 2 circuit at the BCM C4/D harness connector.
  Is there continuity between ground and any of the Brake Signal circuits?
  
  Yes
  - Repair the short to ground in the (B15) Brake Signal 1 or (B16) Brake Signal 2 circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 7
CHECK THE (B15) BRAKE SIGNAL 1 AND (B16) BRAKE SIGNAL 2 CIRCUITS FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM C4/D harness connector.
3. Measure the resistance of the (B15) Brake Signal 1 circuit between the Stop Lamp Switch C1 harness connector and the BCM C4/D harness connector.
4. Measure the resistance of the (B16) Brake Signal 2 circuit between the Stop Lamp Switch C1 harness connector and the BCM C4/D harness connector.
  Is the resistance above 3.0 Ohms for any of the connections?
  
  Yes
  - Repair the open in the (B15) Brake Signal 1 or (B16) Brake Signal 2 circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 8
CHECK RELATED 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 .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.