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 Descriptors

DTC B3410 02: AHLD Front Axle Sensor Signal Circuit Short to Ground
DTC B3410 05: AHLD Front Axle Sensor Signal Circuit Short to Battery or Open
DTC B3410 08: AHLD Front Axle Sensor Signal Circuit Signal Invalid
DTC B3420 02: AHLD Rear Axle Sensor Signal Circuit Short to Ground
DTC B3420 05: AHLD Rear Axle Sensor Signal Circuit Short to Battery or Open
DTC B3420 08: AHLD Rear Axle Sensor Signal Circuit Signal Invalid

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Headlamp Leveling Sensor 5 Volt Reference - Front | B3415 02 | 1 | B3415 01 | --
Headlamp Leveling Sensor 5 Volt Reference - Rear | 1 | 1 | 1 | --
Headlamp Leveling Sensor Signal - Front | B3410 02 | B3410 05 | B3410 05 | B3410 08
Headlamp Leveling Sensor Signal - Rear | B3420 02 | B3420 05 | B3420 05 | B3420 08
Headlamp Leveling Motor Control Circuit 1 - Left | B3435 02 | B3435 05 | B3435 05 | B3435 54
Headlamp Leveling Motor Control Circuit 2 - Left | B3435 02 | B3435 05 | B3435 05 | B3435 54
Headlamp Leveling Motor Control Circuit 3 - Left | B3435 02 | B3435 05 | B3435 05 | B3435 54
Headlamp Leveling Motor Control Circuit 4 - Left | B3435 02 | B3435 05 | B3435 05 | B3435 54
Headlamp Leveling Motor Control Circuit 1 - Right | B3440 02 | B3440 05 | B3440 05 | B3435 54
Headlamp Leveling Motor Control Circuit 2 - Right | B3440 02 | B3440 05 | B3440 05 | B3435 54
Headlamp Leveling Motor Control Circuit 3 - Right | B3440 02 | B3440 05 | B3440 05 | B3435 54
Headlamp Leveling Motor Control Circuit 4 - Right | B3440 02 | B3440 05 | B3440 05 | B3440 39, B3440 54
Headlamp Leveling Sensor Low Reference - Front | -- | 1 | 1 | --
Headlamp Leveling Sensor Low Reference - Rear | -- | 1 | 1 | --
1. Headlamp Leveling Malfunction

### Circuit/System Description

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear headlamp leveling sensors provide the headlamp control module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the headlamp 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 control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.

### Conditions for Running the DTC

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

• | Ignition in the ON or RUN position.

• | Headlamps ON.

### Conditions for Setting the DTC

#### B3410 02 or B3420 02

The headlamp control module detects a short to ground on the headlamp leveling sensor signal circuit.

#### B3410 05 or B3420 05

The headlamp control module detects a short to voltage or an open/high resistance on the headlamp leveling sensor signal circuit.

#### B3410 08 or B3420 08

The headlamp control module detects an invalid signal on the headlamp leveling sensor signal circuit.

### Actions Taken When the DTC Sets

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

• | The driver information center (DIC) will display AFL Lamps Need Service.

• | On vehicles equipped with both AFL and headlamp leveling, the AFL system will remain active.

### 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 cycles have occurred.

### Reference Information

#### Schematic Reference

Headlights 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 leveling sensor.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 1 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the headlamp control module.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.

⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp control module.

⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.

4. Verify the appropriate scan tool Leveling Position Sensor parameter is less than 59 degrees.

⇒ | If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the headlamp control module.

5. Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the appropriate scan tool Leveling Position Sensor parameter is greater than 59 degrees.

⇒ | 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 control module.

6. If all circuits test normal, replace the appropriate headlamp leveling sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Headlamp Leveling Control Module Replacement

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