B1681

B1681-00-REAR HEADLAMP LEVELING SENSOR CIRCUIT PERFORMANCE

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

Theory of Operation

The Front and Rear Headlamp Level Sensors monitor changes in the relative distance between the vehicle body and the front or rear suspension members. The sensor circuitry is energized by the Adaptive Front Lighting System (AFLS) Module and both sensors provide hard wired inputs back to the AFLS Module. The AFLS Module uses these sensor inputs as logic for calculating when and how much to adjust the headlamp beams as part of the Adaptive Front Lighting System (AFLS).

- When Monitored:
Continuously with the ignition on.

- Set Condition:
The Adaptive Front Lighting System (AFLS) Module detects the Headlamp Leveling Sensor Rear Signal circuit is out of range.





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

2. CHECK THE (L964) REAR HEADLAMP LEVELING SENSOR 5 VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE, GROUND, OR AN OPEN/HIGH RESISTANCE




1. Turn the ignition off.
2. Disconnect the Rear Headlamp Level Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (L964) Rear Headlamp Leveling Sensor 5 Volt Supply circuit.

Is the voltage between 4.5 and 5.5 volts?

Yes

- Go To 3

No

- If the voltage is below 4.5 volts, repair the (L964) Rear Headlamp Leveling Sensor 5 Volt Supply circuit for a short to ground or an open/high resistance.
- If the voltage is above 5.5 volts, repair the (L964) Rear Headlamp Leveling Sensor 5 Volt Supply circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (L963) REAR HEADLAMP LEVELING SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE, GROUND, OR AN OPEN/HIGH RESISTANCE




1. Measure the voltage of the (L963) Rear Headlamp Leveling Sensor Signal circuit.

Is the voltage between 4.5 and 5.5 volts?

Yes

- Go To 4

No

- If the voltage is below 4.5 volts, repair the (L963) Rear Headlamp Leveling Sensor Signal circuit for a short to ground or an open/high resistance.
- If the voltage is above 5.5 volts, repair the (L963) Rear Headlamp Leveling Sensor Signal circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (Z922) GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE




1. Turn the ignition off.
2. Measure the resistance between ground and the (Z922) Ground circuit.

Is the resistance above 5.0 Ohms?

Yes

- Repair the (Z922) Ground circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

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