For 1990-2009 cars

### Circuit Description

The suspension position sensors provide the headlamp level controller with front and rear suspension position information. The sensors are permanently grounded and have voltage supplied with the ignition in the ON or CRANK position. The sensors arms are connected to the control arms of the front and rear suspensions. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensors arm. This causes the signal output of the sensors to change. The headlamp level controller compares the information received from the front and rear suspension position sensors and adjusts the headlamp leveling as needed. For more detailed information concerning headlamp leveling operation, refer to Exterior Lighting Systems Description and Operation .

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1010 System Sensors Data Mismatch

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .

DTC Symptom | DTC Symptom Descriptor
--- | ---
52 | Impossible Vehicle Pitch Angle Detected

### Conditions for Running the DTC

The headlamp level controller performs this diagnostic test mode every 51.2 milliseconds when the following conditions are met.

• | The ignition is in the ON or CRANK position.

• | The headlamps are ON.

### Conditions for Setting the DTC

DTC B1010 will set when the headlamp level controller detects a pitch angle that is physically unachievable by the vehicle for 3 consecutive monitoring cycles.

### Action Taken When the DTC Sets

When DTC B1010 sets as current, the following actions are taken:

• | If the headlamp leveling actuators have positioned the headlamps above the nominal level, the headlamp level controller will drive the headlamps to the nominal setting.

• | If the headlamp leveling actuators have positioned the headlamps below the nominal level, the headlamp level controller will disable the headlamp leveling actuators and maintain the lower than nominal level.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | You issue a scan tool CLEAR DTCs command.

• | A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

### Diagnostic Aids

Important: The headlamp level controller is not capable of detecting an actual mechanical failure of the suspension position sensors. When the headlamp level controller determines that the vehicle pitch angle is physically impossible, the headlamp level controller will assume that a mechanical failure has occurred to one of the suspension position sensors.

Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Headlight Leveling Schematics Connector End View Reference: Lighting Systems Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Disconnect the front headlamp leveling suspension position sensor arm from the ball and socket. Refer to Headlamp Leveling Switch Replacement .
4. Move the front suspension position sensor arm up and down.
5. With a scan tool, observe the Front Leveling Position parameter in the headlamp control module data list.

Does the scan tool indicate the front leveling position voltage changes with the movement of the arm?

Go to Step 3

Go to Step 5

3 |

1. Reconnect the front suspension position sensor.
2. Disconnect the rear headlamp leveling suspension position sensor arm from the ball and socket. Refer to Headlamp Leveling Switch Replacement .
3. Move the rear suspension position sensor arm up and down.
4. With a scan tool, observe the Rear Leveling Position parameter in the headlamp control module data list.

Does the scan tool indicate the rear leveling position voltage changes with the movement of the arm?

Go to Step 4

Go to Step 6

4 | Inspect for poor connections at the harness connector of the headlamp leveling control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9
5 | Inspect for poor connections at the harness connectors of the front suspension position sensor and headlamp leveling control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 7
6 | Inspect for poor connections at the harness connector of the rear suspension position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 8
7 | Replace the front suspension position sensor. Refer to Headlamp Leveling Switch Replacement . Did you complete the replacement? | Go to Step 10 | --
8 | Replace the rear suspension position sensor. Refer to Headlamp Leveling Switch Replacement . Did you complete the replacement? | Go to Step 10 | --
9 | Replace the headlamp leveling control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | --
10 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK