The lane departure warning system is controlled by the vehicle direction alert alarm warning (VDAAW) module mounted on the windshield. Lane departure warning is enabled and disabled through a switch located in the headlamp switch assembly. When enabled, the VDAAW module will illuminate the indicator located in the switch.

When the system is operating and can detect the lane markings, the VDAAW module will request via serial data communications that the instrument panel cluster (IPC) illuminate the green lane departure ready-to-assist indicator. If the VDAAW module detects that the vehicle has crosses a lane marking without the turn signal being used, the module will request that the IPC flash the yellow lane departure warning indicator. An audible warning will also sound three times when the yellow IPC indicator is flashing.

Certain factors will affect the operation of the lane departure warning system. When the system is operating properly, the green lane departure indicator will illuminate on the IPC. This indicates that all of the required operating conditions to permit lane departure warning have been met. The green lane departure indicator will not appear when the system is having difficulty seeing the lines on the road or if the view of the camera on the windshield is blocked with mud, dirt, snow, ice, or slush, if the windshield is damaged, or when weather limits visibility, such as while driving in fog, rain, or snow conditions. This is normal operation, the vehicle does not need service. Additionally, lane departure warnings may occasionally occur in a properly operating vehicle due to tar marks, shadows, cracks in the road, or other road imperfections. This is normal system operation and the vehicle does not require service. The driver information center (DIC) may also display LANE DEPARTURE SYSTEM UNAVAILABLE due to the temporary conditions listed above.

Schematic Reference

Object Detection Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Object Detection Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, verify that no antilock brake system, steering wheel position sensor, traction control or stability control DTCs are set.

⇒	If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

Important: When programming the VDAAW, use a Tech 2 and Candi module. Using the MDI to program the VDAAW will result in a failure to complete the programming operation.

2. Program the VDAAW. Refer to Vehicle Direction Alert Alarm Warning Module Programming and Setup.
3. Observe the scan tool Mode Switch parameter while pressing the lane departure warning switch. The parameter should change between Active and Inactive.

⇒	If the parameter does not change between the specified values, refer to Lane Departure Warning Switch Circuit Malfunction.

4. Observe the mode LED while cycling the lane departure warning switch. The LED should turn ON and OFF when cycling between the commanded states.

⇒	If the LED does not turn ON and OFF, refer to Lane Departure Warning Switch LED Circuit Malfunction.

Lane Departure Warning Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for less than 10 ohms between the ground circuit terminal 8 and ground.

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

3. Ignition ON, verify the scan tool Mode Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the VDAAW module.

4. Install 3A fused jumper wire between the signal circuit terminal 9 and ground. Verify the scan tool Mode Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the VDAAW module.

5. If all circuits test normal, test or replace the headlamp switch.

Lane Departure Warning Switch LED Circuit Malfunction

1. Ignition ON, observe the scan tool Mode LED parameter while cycling the lane departure warning switch. The parameter should change between On and Off.

⇒	If the parameter does not change between the specified values, replace the VDAAW module.

2. Observe the mode LED while cycling the lane departure warning switch. The LED should turn ON and OFF when cycling between the commanded states.

⇒	If the LED is always OFF, test the control circuit terminal 16 at the headlamp switch harness connector for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, test or replace the headlamp switch.

3. If all circuits test normal, replace the VDAAW module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.