B1002

DTC B1002

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.

DTC Descriptor

DTC B1002 00
- AHL Module Improper Shutdown

Diagnostic Fault Information






Circuit/System Description

Each headlamp assembly contains a headlamp leveling actuator that is controlled by the headlamp leveling control module. The front and rear suspension position sensors provide the headlamp leveling control module with suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the headlamp leveling control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp leveling control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp leveling control module is wired to each headlamp leveling actuator with 4 directional motor control circuits.

Conditions for Running the DTC

* Battery voltage must be between 9-16 V.

* Ignition ON.

* Low beam headlamps ON.

Conditions for Setting the DTC

The headlamp leveling control module has detected an internal malfunction.

Actions Taken When the DTC Sets

* The headlamp leveling control module commands the headlamps to a default position.

* The headlamp leveling control module disables all headlamp leveling functions.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.

* A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly - Primary

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, exterior lamps OFF, disconnect the harness connector at the K28 headlamp leveling control module. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 5 ohms between the ground circuit terminal 25 and ground.

• If 5 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 5 ohms

3. Ignition ON.

4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

• If the test lamp does not illuminate

1. Ignition OFF, disconnect the X1 harness connector at the X50A fuse block - underhood.

2. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the X50A fuse block - underhood.

• If the test lamp illuminates

5. Test or replace the K28 headlamp leveling control module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

Control Module References Control Module References for headlamp leveling control module replacement, programming, and setup