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Headlamp Leveling Malfunction (TT6 TT2)

Headlamp Leveling Malfunction (TT6 TT2)

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 has overviews of all diagnostic categories.


Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Ignition Left Headlamp

2

2

-

B1461 00

Ignition Right Headlamp

3

3

-

B1462 00

Headlamp Leveling Sensor 5V Reference Front

B3415 02

1

B3415 01

-

Headlamp Leveling Sensor 5V Reference Rear

B3415 02

1

B3415 01

-

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 Sensor Low Reference Front

-

1

-

1

Headlamp Leveling Sensor Low Reference Rear

-

1

-

-

Left Headlamp Ground

-

2

-

B1461 00

Right Headlamp Ground

-

3

-

B1462 00

1. All Headlamp Leveling Actuator Malfunction

2. Left Headlamp Leveling Actuator Malfunction

3. Right Headlamp Leveling Actuator 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 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 (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.

Reference Information

Schematic Reference

Headlights/Daytime Running Lights (DRL) 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 information on diagnostic tools

Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the appropriate headlamp assembly.

2. Test for less than 5 Ω between the ground circuit terminal 8 and ground.

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

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

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

6. If all circuits test normal, replace the appropriate headlamp assembly. Verify that the customer concern is not still present.

7. If the customer concern is still present, 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