Adaptive Forward Lighting Malfunction
Adaptive Forward Lighting 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
Battery positive voltage is applied to the headlamp control module at all times. The headlamp control module has a normal operational voltage range of about 12.5-16 V and is only fully functional with the ignition switch is in the RUN position and the headlamp switch in the AUTOMATIC LIGHT position. The communications enable signal from the body control module (BCM) wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the engine control module, transmission control module, electronic brake control module, and BCM with information regarding power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp 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 and the driver will be notified with a message displayed over the driver information center located on the instrument cluster.
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 Control Module References for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the inline harness connector listed below:
* M29L headlamp leveling actuator-left inline harness connector X111
* M29R headlamp leveling actuator-right inline harness connector X112
2. Test for less than 30 ohm between the ground circuit terminal A and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Engine running, test for less than 30 ohm between the ground circuit terminal E and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
4. Verify that a test lamp illuminates between the control circuit terminal D and ground.
• If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
5. Test for 4.25 V-5.25 V between the signal circuit terminal M and ground.
• 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 K28 headlamp leveling control module.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K28 headlamp leveling control module.
6. If all circuits test normal, test or replace the M29 headlamp leveling actuator
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Headlamp Replacement Headlamp Replacement
* Control Module References Control Module References for headlamp leveling control module replacement, setup, and programming