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Headlamp Leveling Malfunction




Headlamp Leveling Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

Diagnostic Aids

When one of the suspension position sensor voltage reference or sensor signal circuits are shorted to ground, it may not be possible to determine which suspension position sensor voltage reference or sensor signal circuits, front or rear, has failed. If this condition occurs, all suspension position sensor voltage reference and sensor signal circuits will have to be tested for a short to ground.

Reference Information
Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Verification

Ignition ON, with a scan tool perform the Headlamp Motor Test and observe the headlamps. Both headlamps should move UP and DOWN as the test is performed.

If both head lamps do not move UP and DOWN when commanded, refer to Headlamp Leveling Actuator Malfunction.
If both head lamps move UP and DOWN when commanded, refer to Suspension Position Sensor Malfunction.

Circuit/System Testing

Headlamp Leveling Actuator Malfunction
1. Ignition OFF, disconnect the harness connector at the headlamp leveling module.
2. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohm between the ground circuit terminal 24 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, test for B+ between the voltage circuit terminal 12 and ground.

• If less than the specified range, test the voltage circuit for a short to ground or an open/high resistance.

4. Ignition OFF, connect the headlamp leveling control module harness connector.
5. Disconnect the harness connector at the inoperative headlamp leveling actuator.
6. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+.

• If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.

7. Ignition OFF, connect a test lamp between the control circuit terminal 1 and the low reference circuit terminal 2.
8. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.

9. Ignition OFF, connect a test lamp between the control circuit terminal 3 and the low reference circuit terminal 2.
10. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.

11. Ignition OFF, connect a test lamp between the control circuit terminal 4 and the low reference circuit terminal 2.
12. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.

13. Ignition OFF, connect a test lamp between the control circuit terminal 6 and the low reference circuit terminal 2.
14. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.

15. If all circuits test normal, replace the inoperative headlamp leveling actuator.

Suspension Position Sensor Malfunction - Front
1. Ignition OFF, disconnect the harness connector at the LF suspension position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal C.

• If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.

3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground.

• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.

4. Verify the scan tool Front Leveling Position Sensor parameter is less than 0.5 V.

• If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.

5. Install a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Front Leveling Position Sensor parameter is greater than 4.49 V.

• If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.

6. If all circuits test normal, test or replace the LF suspension position sensor.

Suspension Position Sensor Malfunction - Rear
1. Ignition OFF, disconnect the harness connector at the LR suspension position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal C.

• If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.

3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground.

• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.

4. Verify the scan tool Rear Leveling Position Sensor parameter is less than 0.5 V.

• If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.

5. Install a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Rear Leveling Position Sensor parameter is greater than 4.49 V.

• If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.

6. If all circuits test normal, test or replace the LR suspension position sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Headlamp Replacement (Headlamp Replacement)
* Headlamp Leveling Front Suspension Height Sensor Replacement (Headlamp Leveling Front Suspension Height Sensor Replacement)
* Headlamp Leveling Rear Suspension Height Sensor Replacement (Headlamp Leveling Rear Suspension Height Sensor Replacement)
* Control Module References (Programming and Relearning)for headlamp leveling module replacement, setup, and programming

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