DTC B356A (GMC)
Diagnostic InstructionsDTC Descriptor
DTC B356A

Vehicle Direction Warning Switch Circuit

Symptom Byte Information:Symptom Byte List

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Signal—Terminal 10@B174W Frontview Camera - Windshield

B356A 02, 1

1

B356A 05, 1

—

Ground—Terminal 10@S126 Drive Mode Select Switch

—

1

1

—

1.Lane Departure Warning=Malfunction

Circuit/System Description

Component

Description

S126 Drive Mode Select Switch

The assembly contains individual switches.Each function has its own switch. The switches are connected to a resistor ladder so that a specific resistance is generated for each switch.

B174W Frontview Camera - Windshield

The video camera and the control module are a single serviceable component.

This camera delivers live video of what is in front of the vehicle. The video can be used for several functions, like lane departure warning, lane keep assist, road sign recognition and more.

The control module also reads various switches and sensors and makes their values available via serial data.

K9 Body Control Module

Depending on the version, the control module can support different functions:

  • Exterior Illumination
  • Interior Illumination
  • Steering Wheel Controls
  • Power Mode Control

The control module also reads various switches and sensors and makes their values available via serial data.

Conditions for Running the DTC

Ignition » On / Vehicle » In Service Mode

Conditions for Setting the DTCDTC B356A 05

Control Circuit=Short to Voltage

B356A 02

Control Circuit=Short to Ground

Actions Taken When the DTC Sets
  • Lane Departure Warning=Inoperative
  • Driver Information Center Display—Service Driver Assist
Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

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 Schematics

Connector End View Reference

Master Electrical Component List

Description and Operation

Lane Departure Warning Description and Operation

Electrical Information ReferenceScan Tool Reference

Control Module References

Circuit/System Verification
  1. Ignition » On / Vehicle » In Service Mode
  2. Operate the component:Lane Departure Warning Switch»Cycle On and Off

    Verify the scan tool parameter:Lane Departure Warning Switch Status=Active/Inactive—The value should change when selecting the different switch positions.

    • If not the specified values

      Refer to: Circuit/System Testing

    • If the specified values
  3. All OK.

Circuit/System Testing

    Note: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems » Off
  2. Disconnect the electrical connector:S126 Drive Mode Select Switch
  3. Test for less than 15 Ω between the test points:Ground circuit terminal 10&Ground
    • If 15 Ω or greater
    1. Test for less than 2 Ω between the test points:Ground circuit terminal 10&The other end of the circuit
      • 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.
    • If less than 15 Ω
  4. Ignition » On / Vehicle » In Service Mode
  5. Verify the scan tool parameter:Lane Departure Warning Switch=Inactive
    • If not the specified state
    1. Ignition/Vehicle » Off
    2. Disconnect the electrical connector:B174W Frontview Camera - Windshield
    3. Test for infinite resistance between the test points:Signal circuit terminal 10@Component harness&Ground
      • If less than infinite resistance » Repair the short to ground on the circuit.
      • If infinite resistance » Replace the component:B174W Frontview Camera - Windshield
    • If the specified state
  6. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 13&Ground
  7. Verify the scan tool parameter:Parking Assist Switch=Active
    • If not the specified state
    1. Ignition/Vehicle » Off & Remove » Jumper wire(s)
    2. Disconnect the electrical connector:B174W Frontview Camera - Windshield
    3. Ignition » On / Vehicle » In Service Mode
    4. Test for less than 1 V between the test points:Signal circuit terminal 13@Component harness&Ground
      • If 1 V or greater » Repair the short to voltage on the circuit.
      • If less than 1 V
    5. Ignition/Vehicle » Off
    6. Test for less than 2 Ω between the test points:Signal circuit terminal 13@Component harness&Terminal 10@Control module harness
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Replace the component:B174W Frontview Camera - Windshield
    • If the specified state
  8. Test or replace the component:S126 Drive Mode Select Switch
Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair:Diagnostic Repair Verification