B1017-18

B1017-18-REVERSE LAMP - UNDER CURRENT

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The BCM receives a communication network message to indicate that the vehicle is in reverse. Once the BCM is informed that the vehicle is in reverse, it provides a voltage output through the backup lamp driver circuit. The same BCM driver circuit connects to both the Left and Right Backup Lamps. A ground path for the lamps is present through the harness to the body sheet metal. For additional information on the Backup Lamps operation, Exterior Lamps - Operation.

- When Monitored:
With the backup lamps on.

- Set Condition:
When the Body Control Module (BCM) detects less than expected current draw in the (L15) Left Backup Lamp Driver circuit and (L16) Right Backup Lamp Driver circuit.





1. CHECK FOR AN INTERMITTENT CONDITION

NOTE: This DTC will set when either the Left or Right Backup Lamp bulb is burnt out or missing.

1. Turn the ignition on.
2. With the scan tool, clear all DTCs.
3. With the brakes firmly applied, shift the gear selector into REVERSE.
4. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- Test complete, 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.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE (L15) LEFT BACKUP LAMP DRIVER CIRCUIT AND (L16) RIGHT BACKUP LAMP DRIVER CIRCUITS FOR AN OPEN IN THE HARNESS
1. Shift the gear selector into PARK.
2. Turn the ignition off.
3. Disconnect the Left Tail Lamp Assembly C1 harness connector.
4. Disconnect the Right Tail Lamp Assembly C1 harness connector.
5. Disconnect the BCM C2 harness connector.
6. Measure the resistance of the (L15) Left Backup Lamp Driver circuit between the Left Tail Lamp Assembly C1 harness connector and the BCM C2 harness connector.
7. Measure the resistance of the (L16) Right Backup Lamp Driver circuit between the Right Tail Lamp Assembly C1 harness connector and the BCM C2 harness connector.

Are the resistances below 5.0 Ohms?

Yes

- Go To 3

No

- Repair the open in the (L15) Left Backup Lamp Driver circuit or (L16) Right Backup Lamp Driver circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (Z941) GROUND CIRCUITS FOR AN OPEN IN THE HARNESS
1. Using a 12-volt test light connected to 12-volts, check the (Z941) Ground circuit at the Left Tail Lamp Assembly C1 harness connector.
2. Using a 12-volt test light connected to 12-volts, check the (Z941) Ground circuit at the Right Tail Lamp Assembly C1 harness connector.

Does the test light illuminate brightly for both circuits?

Yes

- Go To 4

No

- Repair the open in the appropriate (Z941) Ground circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE BCM FOR CORRECT OPERATION
1. Turn the ignition off.
2. Reconnect the BCM C2 harness connector.
3. Connect a 12-volt test light between the (L15) Left Backup Lamp Driver circuit and the (Z941) Ground circuit at the Left Tail Lamp Assembly C2 harness connector.
4. Turn the ignition on.
5. With the brakes firmly applied, shift the gear selector into REVERSE.

Does the test light illuminate brightly?

Yes

- Replace the Left or Right Backup Lamp bulb based on the original concern. Tail Stop Turn Lamp - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the BCM. Body Control Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.