Buick Regal: DTC B356A

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 B356A 02

Vehicle Direction Warning Switch Circuit Short to Ground

DTC B356A 05

Vehicle Direction Warning Switch Circuit Short to Voltage

Diagnostic Fault Information

1. Lane Departure Warning Malfunction

Circuit/System Description

The lane departure warning system is controlled by the Active Safety Control Module. Lane departure warning is enabled and disabled through a switch located in the instrument panel. When enabled, the Active Safety Control Module will illuminate the indicator located in the switch.

When the Frontview Camera module is operating and can detect the lane markings, the Frontview Camera module will request via serial data communications that the instrument panel cluster illuminate the green lane departure ready - to - assist indicator. If the Frontview Camera module detects that the vehicle has crossed a lane marking without the turn signal being used, the module will request that the instrument cluster flash the yellow lane departure warning indicator. An audible warning may also sound three times or the haptic seat (if equipped) may pulse when the yellow Instrument Cluster indicator is flashing. The driver can select between audible or haptic alerts in the vehicle personalization menu. See the Owner's Manual for more detailed information on vehicle personalization.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

DTC B356A 02

The Active Safety Control Module has detected a short to ground for more than 10 s.

TC B356A 05

The Active Safety Control Module has detected a short to voltage or an open/high resistance for more than 10 s.

Action Taken When the DTC Sets

• Lane departure warning is disabled.
• Service Lane Departure is displayed on the driver information center.

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 pressing the lane departure warning switch for an extended length of time will cause this DTC to set.

Reference Information

Schematic Reference

Driver Assistance Systems Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Active Safety System 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

1. Ignition ON.

2. Verify the scan tool Vehicle Direction Warning Switch Status parameter changes between On and Off while cycling the lane departure warning switch.

• If the parameter does not change

Refer to Circuit/System Testing.

• Go to next step: If the parameter changes

3. All OK.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S48A Multifunction Switch - Instrument Panel. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the ground circuit terminal 7 and ground.

• If 10 Ω or greater

1. Test for less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If less than 10 Ω

3. Ignition ON.

4. Verify the scan tool Vehicle Direction Warning Switch Status parameter is Off.

• If not Off

1. Ignition OFF, disconnect the harness connector at the K124 Active Safety Control Module.
2. Test for infinite resistance between the S48A Multifunction Switch - Instrument Panel signal circuit terminal 4 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • If infinite resistance, replace the K109 Frontview Camera Module.

• Go to next step: If Off

5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and ground circuit terminal 7.

6. Verify within 10 s the scan tool Vehicle Direction Warning Switch Status parameter is On

• If not On

1. Ignition OFF, disconnect harness connector at the K124 Active Safety Control Module.

   Ignition ON.

2. Test for less than 1 V between the S48A Multifunction Switch - Instrument Panel signal circuit terminal 4 and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • Go to next step: If less than 1 V.
3. Test for less than 2 Ω in the signal circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K124 Active Safety Control Module.

• Go to next step: If On

7. Test or replace the S48A Multifunction Switch - Instrument Panel.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for control module replacement, programming, and setup.

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