For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC B3435 00: Automatic Headlamp Leveling Control Module Left Servo Driver 1 or 2 Circuit Malfunction
DTC B3440 00: Automatic Headlamp Leveling Control Module Right Servo Driver 1 or 2 Circuit Malfunction

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Left Headlamp | 1 | 1 | -- | B3435 00
Ignition Right Headlamp | 2 | 2 | -- | B3440 00
Left Headlamp Ground | -- | 1 | -- | B3435 00
Right Headlamp Ground | -- | 2 | -- | B3440 00
1. Left Headlamp Leveling Malfunction 2. Right Headlamp Leveling Malfunction

### 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 AUTO 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 (ECM), transmission control module (TCM), electronic brake control module (EBCM), 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.

### Conditions for Running the DTC

• | Battery voltage must be between 9-16 V.

• | The ignition is in the ON or RUN position.

• | The headlamps are ON.

### Conditions for Setting the DTC

#### B3435 00 or B3440 00

The DTC will set when the headlamp control module detects no signal and low voltage on the sensor signal line.

### Action Taken When the DTC Sets

• | The headlamp control module disables the headlamp leveling system.

• | Service head light leveling indication ON.

• | Advanced front lighting system fault indication ON.

### Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists.

### Reference Information

#### Schematic Reference

Headlight Leveling Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exterior Lighting Systems Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate headlamp assembly.
2. Ignition OFF, test for less than 5 Ω between the ground circuit terminal 8 and ground.

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

3. Ignition ON, headlamps ON, connect a test lamp between the ignition circuit terminal 6 and ground. The test lamp should illuminate.

⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

4. If all circuits test normal, replace the appropriate headlamp assembly. Verify that the DTC do not reset.

⇒ | If the DTC resets, replace the K26 Headlamp Control Module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Headlamp Replacement

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