B3440
DTC B3435 or B3440
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 Descriptors
DTC B3435 00
- AHLD Left Servo Driver Circuit
DTC B3435 02
- AHLD Left Servo Driver Circuit Short to Ground
DTC B3435 39
- AHLD Left Servo Driver Circuit Internal Electronic Failure
DTC B3435 54
- AHLD Left Servo Driver Circuit Over Temperature
DTC B3440 00
- AHLD Right Servo Driver Circuit
DTC B3440 02
- AHLD Right Servo Driver Circuit Short to Ground
DTC B3440 39
- AHLD Right Servo Driver Circuit Internal Electronic Failure
DTC B3440 54
- AHLD Right Servo Driver Circuit Over Temperature
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 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 actuator control circuits.
Conditions for Running the DTC
* Battery voltage must be between 9-16 V.
* Ignition ON.
* Headlamps ON.
Conditions for Setting the DTC
DTC B3435 00
The headlamp leveling control module detects a short to voltage or an open/high resistance in any of the left actuator control circuits.
DTC B3435 02
The headlamp leveling control module detects a short to ground in any of the left actuator control circuits.
DTC B3435 39
The headlamp leveling control module detects an internal electronic failure.
DTC B3435 54
The headlamp leveling control module detects an overheating condition in any of the left actuator control circuits.
DTC B3440 00
The headlamp leveling control module detects a short to voltage or an open/high resistance in any of the right actuator control circuits.
DTC B3440 02
The headlamp leveling control module detects a short to ground in any of the right actuator control circuits.
DTC B3440 39
The headlamp leveling control module detects an internal electronic failure.
DTC B3440 54
The headlamp leveling control module detects an overheating condition in any of the right actuator control circuits.
Actions Taken When the DTC Sets
* When DTC B3435 or DTC B3440 sets, the headlamp leveling control module will attempt to return the lamps to a nominal position and disable all requests to all headlamp actuators.
* The instrument cluster will display Headlamp Leveling Malfunction - Contact Service.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists and the ignition is cycled.
* 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 appropriate M29 headlamp leveling actuator. It may take up to 2 minutes for all vehicle systems to power down.
2. Remove the F39UA 5 A fuse from the X50A fuse block - underhood.
3. Test for 10 ohms -25k ohms between each control circuit terminal listed below and ground.
* M29 headlamp leveling actuator control terminal 1
* M29 headlamp leveling actuator control terminal 2
* M29 headlamp leveling actuator control terminal 3
* M29 headlamp leveling actuator control terminal 4
• If less than 10 ohms
1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module.
2. Test for infinite resistance between the appropriate control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K28 headlamp leveling control module.
• If greater than 25k ohms
1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module.
2. Test for less than 2 ohms in the appropriate control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms
3. Ignition ON.
4. Test for less than 1 V between the appropriate control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K28 headlamp leveling control module.
• If between 10 ohms -25k ohms
4. Ignition OFF, install the F39UA 5 A fuse at the X50A fuse block - underhood, ignition ON, headlamps ON.
5. Verify a test lamp does not illuminate between each control circuit terminal listed below and ground.
* M29 headlamp leveling actuator control terminal 1
* M29 headlamp leveling actuator control terminal 2
* M29 headlamp leveling actuator control terminal 3
* M29 headlamp leveling actuator control terminal 4
• If the test lamp illuminates
1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module, ignition ON.
2. Test for less than 1 V between the appropriate control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K28 headlamp leveling control module.
• If the test lamp does not illuminate
6. Test or replace the appropriate M29 headlamp leveling actuator.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Headlamp Replacement Headlamp Replacement
* Control Module References Control Module References for headlamp leveling control module replacement, programming, and setup