GM Service Manual Online
For 1990-2009 cars only

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 Descriptor

DTC B356A 02: Vehicle Direction Alert Alarm Warning Switch Circuit Short to Ground

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Vehicle Direction Alert Alarm Warning Module B+

1

1

--

--

Lane Departure Warning Switch Signal

B356A 02

1

1

--

Lane Departure Warning Indicator Control Circuit

1

B0987 04

B0987 01

--

Vehicle Direction Alert Alarm Warning Module Ground

--

1

--

--

1. Lane Departure Warning Malfunction

Circuit/System Description

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.

Conditions for Running the DTC

Ignition ON

Conditions for Setting the DTC

A short to ground is detected on the switch signal circuit.

Action Taken When the DTC Sets

    • Lane departure warning is disabled
    • SERVICE LANE DEPARTURE SYSTEM is displayed on the DIC.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Diagnostic Aids

Manually depressing the lane departure warning on/off switch for an extended length of time will cause this DTC to set.

Reference Information

Schematic Reference

Object Detection Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Object Detection 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 scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Mode Switch parameter while pressing and releasing the lane departure warning switch. The parameter should change between Active and Inactive.

Circuit/System Testing

  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.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Mode Switch parameter is Inactive.
  5. 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.
  6. Install 3A fused jumper wire between the signal circuit terminal 9 and ground. Verify the scan tool Mode Switch parameter is Active.
  7. 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.
  8. If all circuits test normal, test or replace the headlamp switch.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Test for infinite resistance between the signal circuit terminal 9 and the ground circuit terminal 8 with the switch in the open position.
  3. If the specified value, replace the headlamp switch.
  4. Test for less than 2 ohms between the signal circuit terminal 9 and the ground circuit terminal 8 with the switch in the closed position.
  5. If greater than the specified range, replace the headlamp switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Headlamp Switch Replacement
    •  Control Module References for VDAAW module replacement, setup and programming