Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Turn the Headlamps on.
2. With the scan tool, read the Body Control Module (BCM) DTCs and record on the repair order.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension. If no problems are found, test complete.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (L43) LEFT LOW BEAM DRIVER CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the Headlamps off.
2. Turn the ignition off.
3. Disconnect the Left Front Lamp Assembly harness connector.
4. Disconnect the BCM C1/A harness connector.
5. Turn the ignition on.
6. Measure the voltage between ground and the (L43) Left Low Beam Driver circuit at the BCM C1/A harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (L43) Left Low Beam Driver circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (L43) LEFT LOW BEAM DRIVER CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Measure the resistance of the (L43) Left Low Beam Driver circuit between the Left Front Lamp Assembly harness connector and the BCM C1/A harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the open in the (L43) Left Low Beam Driver circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE GROUND CIRCUITS FOR AN OPEN
1. Measure the resistance between ground and the (Z901) Ground circuit at the Left Front Lamp Assembly harness connector.
2. Measure the resistance between ground and the (Z902) Ground circuit at the Left Front Lamp Assembly harness connector.
  Is the resistance below 3.0 Ohms for both connections?
  
  Yes
  - Go To 5
  No
  - Repair the open in the appropriate Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE BCM
1. Reconnect the BCM C1/A harness connector.
2. Turn the ignition on.
3. Turn the Headlamps on.
  NOTE:
  The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
4. Connect a 12-volt test light between the (L43) Left Low Beam Driver circuit and the (Z901) Ground circuit at the Left Front Lamp Assembly harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Replace the Left Low Beam Bulb in accordance with the Service Information. Refer to UNIT, FRONT LAMP, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - 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 .