B1459
DTC B1459
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 B1459 02
- AHLD Right Servo Driver Terminal 3 Circuit Short to Ground
DTC B1459 05
- AHLD Right Servo Driver Terminal 3 Circuit Short to Battery or Open
Diagnostic Fault Information
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
Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
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 (Programming and Relearning)for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the right headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+.
• 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.
3. Ignition OFF, connect a test lamp between the control circuit terminal 4 and the low reference circuit terminal 2.
4. 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 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.
5. If all circuits test normal, replace the right headlamp leveling actuator.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Headlamp Replacement (Headlamp Replacement)
* Control Module References (Programming and Relearning)for headlamp leveling module replacement, setup, and programming