LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2017 >> ATS Base, 4D Sedan, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 264 (Object Detection System And Pedestrian Protection System - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Lane Departure Warning System Malfunction >> Circuit/System Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Testing

WARNING: This page is about a different car, the 2016 Cadillac CT6. However, it is still accessible from the selected car via links, so may be relevant.

Lane Departure Warning Switch Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the S70A Steering Wheel Controls Switch - Left Lower. Ignition ON.
  2. Test for 12 V between the 12 V reference circuit terminal 3 and ground.
    • If less than 12 V 
    1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the 12 V reference circuit and ground
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the 12 V reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If 12 V 
  3. Ignition ON.
  4. Verify the scan tool Lane Departure Warning Switch parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF, disconnect the harness connector at the K109 Frontview Camera Module.
    2. Test for infinite resistance between the S70A Steering Wheel Controls Switch - Left Lower signal circuit terminal 2 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 Body Control Module.
    • If Inactive 
  5. Test or replace the S70A Steering Wheel Controls Switch - Left Lower.

Lane Departure Warning Switch Indicator Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the S70A Steering Wheel Controls Switch - Left Lower, ignition ON.
    2. NOTE:

    Verify interior lighting dimming is turned all the way up.

  2. Test for 6.2-10.9 V between the dimming control circuit terminal 4 and ground.
    • If less than 6.2 V 
    1. Ignition OFF, disconnect the harness connector at the S70D Steering Wheel Controls Switch - Right Upper.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the S70D Steering Wheel Controls Switch - Right Upper.
    • If greater than 10.9 V 
    1. Ignition OFF, disconnect the harness connector at the S70D Steering Wheel Controls Switch - Right Upper, ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the S70D Steering Wheel Controls Switch - Right Upper.
    • If between 6.2-10.9 V 
  3. Connect a test lamp between the control circuit terminal 5 and B+.
  4. Verify the test lamp turns ON and OFF when commanding the Lane Departure Warning Indicator ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the K109 Frontview Camera Module (without UGN) OR K124 Active Safety Control Module (With UGN), ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Ignition OFF.
    4. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the S70A Steering Wheel Controls Switch - Left Lower.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the K109 Frontview Camera Module (without UGN) OR K124 Active Safety Control Module (With UGN).
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K109 Frontview Camera Module (without UGN) OR K124 Active Safety Control Module (With UGN).
    • If the test lamp turns ON and OFF 
  5. Test or replace the S70A Steering Wheel Controls Switch - Left Lower.
scientia non olet · About LEMON Manuals