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 B1459 02: AHLD Right Servo Driver Terminal 3 Circuit Short to GroundDTC B1459 05: AHLD Right Servo Driver Terminal 3 Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Headlamp Leveling Module B+ | 1 | 1 | -- | -- |
Suspension Position Sensor - Front Voltage Reference | B3410 02, 2 | B3410 03, 2 | B3410 07, 2 | -- |
Suspension Position Sensor - Rear Voltage Reference | B3420 02, 3 | B3420 03, 3 | B3420 07, 3 | -- |
Suspension Position Sensor - Front Signal | B3410 02, 2 | B3410 03, 2 | B3410 07, 2 | -- |
Suspension Position Sensor - Rear Signal | B3420 02, 3 | B3420 03, 3 | B3420 07, 3 | -- |
Headlamp Leveling Motor (1) Control - Left | B2667 02 | B2667 05 | B2667 05 | -- |
Headlamp Leveling Motor (2) Control - Left | B2672 02 | B2672 05 | B2672 05 | -- |
Headlamp Leveling Motor (3) Control - Left | B1457 02 | B1457 05 | B1457 05 | -- |
Headlamp Leveling Motor (4) Control - Left | B1458 02 | B1458 05 | B1458 05 | -- |
Headlamp Leveling Motor (1) Control - Right | B2677 02 | B2677 05 | B2677 05 | -- |
Headlamp Leveling Motor (2) Control - Right | B2682 02 | B2682 05 | B2682 05 | -- |
Headlamp Leveling Motor (3) Control - Right | B1459 02 | B1459 05 | B1459 05 | -- |
Headlamp Leveling Motor (4) Control - Right | B1460 02 | B1460 05 | B1460 05 | -- |
Headlamp Leveling Motor - Left Low Reference | -- | 1 | -- | -- |
Headlamp Leveling Motor - Right Low Reference | -- | 1 | -- | -- |
Headlamp Leveling Actuator - Left Ground | -- | 1 | -- | -- |
Headlamp Leveling Actuator - Right Ground | -- | 1 | -- | -- |
Headlamp Leveling Module Ground | -- | 1 | -- | -- |
Suspension Position Sensor - Front Low Reference | -- | 2 | -- | -- |
Suspension Position Sensor - Rear Low Reference | -- | 3 | -- | -- |
1. Headlamp Leveling Malfunction 2. Suspension Position Sensor Malfunction - Front 3. Suspension Position Sensor Malfunction - Rear | ||||
Circuit Description
The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling 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.
Conditions for Running the DTC
The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met:
| • | The ignition is in the ON or CRANK position. |
| • | The headlamps are ON. |
Conditions for Setting the DTC
B1459 02
This DTC will set when the headlamp leveling module detects a short to ground in the right headlamp leveling actuator motor 3 control circuit after 4 consecutive monitoring cycles.
B1459 05
This DTC will set when the headlamp leveling module detects an open or short to voltage in the right headlamp leveling actuator motor 3 control circuit after 4 consecutive monitoring cycles.
Action Taken When the DTC Sets
When DTC B1459 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the right headlamp leveling actuator.
- Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+.
- Ignition OFF, connect a test lamp between the control circuit terminal 4 and the low reference circuit terminal 2.
- Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed.
- If all circuits test normal, replace the right headlamp leveling actuator.
| ⇒ | If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module. |
| ⇒ | If the test lamp is always ON, test the control circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. |
| ⇒ | If the test lamp is always OFF, test the control circuit terminal 4 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for headlamp leveling module replacement, setup, and programming |
