B2126

B2126-00-SENSOR SUPPLY VOLTAGE LOW





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

Theory of Operation

The Front and Rear Headlamp Level Sensors share a common 5 Volt Supply circuit from the Adaptive Front Lighting System (AFLS) Module.

- When Monitored:
With the ignition on.

- Set Condition:
The Adaptive Front Lighting System (AFLS) Module detects an open, short to battery, or short to ground on the Headlamp Leveling Sensor 5 Volt Supply circuit.





1. CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. 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.

2. FRONT HEADLAMP LEVEL SENSOR
1. Turn the ignition off.
2. Disconnect Front Headlamp Level Sensor.
3. Turn the ignition on.
4. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 3

No

- Replace Front Headlamp Level Sensor. Front.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. REAR HEADLAMP LEVELING SENSOR
1. Turn the ignition off.
2. Disconnect Rear Headlamp Level Sensor.
3. Turn the ignition on.
4. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 4

No

- Replace Rear Headlamp Level Sensor. Rear.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (L961) HEADLAMP LEVELING SENSOR 5 VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE





NOTE: Perform this step with the Front and Rear Level Sensors disconnected.

1. Turn the ignition off.
2. Disconnect the Adaptive Front Lighting System (AFLS) Module harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit.

Is voltage present?

Yes

- Repair the short to voltage on the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 5

5. CHECK THE (L961) HEADLAMP LEVELING SENSOR 5 VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND





NOTE: Perform this step with the Front and Rear Level Sensors disconnected.

1. Turn the ignition off.
2. Measure the resistance between ground and the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the short to ground on the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 6

6. CHECK THE (L961) HEADLAMP LEVELING SENSOR 5 VOLT SUPPLY CIRCUIT FOR AN OPEN OR HIGH RESISTANCE




1. Measure the resistance of the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit.

Is the resistance above 5.0 Ohms?

Yes

- Repair the open or high resistance on the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Adaptive Front Lighting System (AFLS) Module. Adaptive Front Lighting System Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.