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Home >> Cadillac >> 2018 >> CT6 Plug-In >> Repair and Diagnosis >> Accessories & Equipment >> Drivers Assistance Systems - ADAS >> Driver Assistance Systems >> Diagnostic Information and Procedures >> DTC B0987 >> Circuit/System Testing
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Circuit/System Testing

Without UGN or UKL

    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: S70A Steering Wheel Controls Switch - Left Lower
    3. NOTE:

    Verify interior lighting dimming is turned all the way up.

  3. Test for 4 to 11 V between the test points: Control circuit terminal 4 & Ground
    • If less than 4 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: S70D Steering Wheel Controls Switch - Right Upper
    3. Test for infinite resistance between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Control circuit terminal 4 @ S70A Steering Wheel Controls Switch - Left Lower
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If greater than 11 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: S70D Steering Wheel Controls Switch - Right Upper
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Ground
      • If greater than 1 V

        Repair the short to voltage on the circuit.

      • If 1 V or less

        Replace the component: S70D Steering Wheel Controls Switch - Right Upper

    • Go to next step: If between 4 - 11 V 
  4. Ignition - On/Vehicle - In Service Mode
  5. Connect a test lamp between the test points: Control circuit terminal 5 @ S70A Steering Wheel Controls Switch - Left Lower & B+
  6. Perform the appropriate scan tool control function: Lane Departure Warning Indicator Command - Cycle On and Off
    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X1 B174W Frontview Camera - Windshield
    3. Test for less than 2 ohms between the test points: Control circuit terminal 5 @ Component harness & Terminal 4 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: B174W Frontview Camera - Windshield
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: B174W Frontview Camera - Windshield
    3. Test for infinite resistance between the test points: Terminal 4 @ 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
    • Go to next step: If the test lamp turns On and Off 
  7. Test or replace the component: S70A Steering Wheel Controls Switch - Left Lower

With UGN

    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: S70A Steering Wheel Controls Switch - Left Lower
    3. NOTE:

    Verify interior lighting dimming is turned all the way up.

  3. Test for 4 to 11 V between the test points: Control circuit terminal 4 & Ground
    • If less than 4 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: S70D Steering Wheel Controls Switch - Right Upper
    3. Test for infinite resistance between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Control circuit terminal 4 @ S70A Steering Wheel Controls Switch - Left Lower
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If greater than 11 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: S70D Steering Wheel Controls Switch - Right Upper
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Ground
      • If greater than 1 V

        Repair the short to voltage on the circuit.

      • If 1 V or less

        Replace the component: S70D Steering Wheel Controls Switch - Right Upper

    • Go to next step: If between 4 - 11 V 
  4. Ignition - On/Vehicle - In Service Mode
  5. Connect a test lamp between the test points: Control circuit terminal 5 @ S70A Steering Wheel Controls Switch - Left Lower & B+
  6. Perform the appropriate scan tool control function: Lane Departure Warning Indicator Command - Cycle On and Off
    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X1 K124 Active Safety Control Module
    3. Test for less than 2 ohms between the test points: Control circuit terminal 5 @ Component harness & Terminal 3 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K124 Active Safety Control Module
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: K124 Active Safety Control Module
    3. Test for infinite resistance between the test points: Terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K124 Active Safety Control Module
    • Go to next step: If the test lamp turns On and Off 
  7. Test or replace the component: S70A Steering Wheel Controls Switch - Left Lower

With UKL

    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: S70A Steering Wheel Controls Switch - Left Lower
    3. NOTE:

    Verify interior lighting dimming is turned all the way up.

  3. Test for 4 to 11 V between the test points: Control circuit terminal 4 & Ground
    • If less than 4 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: S70D Steering Wheel Controls Switch - Right Upper
    3. Test for infinite resistance between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Control circuit terminal 4 @ S70A Steering Wheel Controls Switch - Left Lower
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If greater than 11 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: S70D Steering Wheel Controls Switch - Right Upper
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 7 @ S70D Steering Wheel Controls Switch - Right Upper & Ground
      • If greater than 1 V

        Repair the short to voltage on the circuit.

      • If 1 V or less

        Replace the component: S70D Steering Wheel Controls Switch - Right Upper

    • Go to next step: If between 4 - 11 V 
  4. Ignition - On/Vehicle - In Service Mode
  5. Connect a test lamp between the test points: Control circuit terminal 5 @ S70A Steering Wheel Controls Switch - Left Lower & B+
  6. Perform the appropriate scan tool control function: Lane Departure Warning Indicator Command - Cycle On and Off
    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X1 K124A Active Safety Control Module 1
    3. Test for less than 2 ohms between the test points: Control circuit terminal 5 @ Component harness & Terminal 9 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K124A Active Safety Control Module 1
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: K124A Active Safety Control Module 1
    3. Test for infinite resistance between the test points: Terminal 9 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K124A Active Safety Control Module 1
    • Go to next step: If the test lamp turns On and Off 
  7. Test or replace the component: S70A Steering Wheel Controls Switch - Left Lower
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