Diagnostic Test

1) CHECK FOR DTCs IN THE BCM
Turn the ignition on.

With the scan tool, read BCM DTCs.

Does the scan tool display any DTCs?

Yes
1. Diagnose and repair the DTC(s) Refer to the DTC INDEX Table in the applicable article for the diagnostic procedure(s).
2. Perform VTSS VERIFICATION TEST - 1A .
No
1. Go to step 2).
2) CHECK HAZARD LAMP OPERATION USING THE HAZARD SWITCH
Operate the Hazard Lamps with the Hazard Switch.

Do the hazard lamps operate?

Yes
1. Go to step 3).
No
1. Diagnose and repair the hazard lamps. Refer to DIAGNOSIS AND TESTING .
2. Perform VTSS VERIFICATION TEST - 1A .
3) ACTUATE THE HAZARD LAMPS WITH THE SCAN TOOL
Turn the Hazard Switch off.

With the scan tool in BCM, actuate the Hazard Lamps.

Do the Hazard Lamps operate?

Yes
1. Replace and program the BCM in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST .
No
1. Go to step 4).
4) CHECK (L91) HAZARD LAMP CONTROL CIRCUIT FUNCTION
Using the scan tool, turn the Hazard Lamp actuator off.

Turn the ignition off.

Disconnect the BCM C1 harness connector.

Connect a jumper wire between the (L91) Hazard Lamp Control circuit and ground.

Do the Hazard Lamps operate?

Yes
1. Replace and program the BCM in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST .
No
1. Go to step 5).
5) CHECK (L91) HAZARD LAMP CONTROL CIRCUIT FOR AN OPEN
Disconnect the Hazard Switch harness connector.

Measure the resistance of the (L91) Hazard Lamp Control circuit between the BCM C1 harness connector and the Hazard Switch harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Replace the Hazard Switch in accordance with the Service Information.
2. Perform VTSS VERIFICATION TEST - 1A .
No
1. Repair the (L91) Hazard Lamp Control circuit for an open.
2. Perform VTSS VERIFICATION TEST - 1A .