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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 89 (Driver Assistance Systems) >> Diagnostic Information and Procedures >> DTC B0987 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector:S155 Lane Departure Warning Switch
  3. Ignition - On / Vehicle - In Service Mode
    4. NOTE:

    Verify interior lighting dimming is turned all the way up.

  4. Test for 4 to 11 V between the test points:Control circuit terminal 5 & Ground
    • If less than 4 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:X3@K9 Body Control Module
    3. Test for infinite resistance between the test points:Control circuit terminal 5@Component harness & 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 5@Component harness & Control circuit terminal 25@Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component:K9 Body Control Module
    • If greater than 11 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:X3@K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:Control circuit terminal 5@Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component:K9 Body Control Module
    • Go to next step: If between 4 - 11 V 
  5. Ignition/Vehicle & All vehicle systems - Off
  6. Connect the electrical connector:S155 Lane Departure Warning Switch
  7. Disconnect the electrical connector:B174W Frontview Camera - Windshield
  8. Ignition - On / Vehicle - In Service Mode
  9. Verify the component is not activated:Lane Departure Warning Indicator
    • If the component is On 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:S155 Lane Departure Warning Switch
    3. Test for infinite resistance between the test points:Control circuit terminal 7@Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component:S155 Lane Departure Warning Switch
    • Go to next step: If the component is Off 
  10. Connect a 3 A fused jumper wire between the test points:Terminal 4 & Ground
  11. Verify the component is activated:Lane Departure Warning Indicator
    • If the component is Off 
    1. Ignition/Vehicle - Off
    2. Remove - Jumper Wire
    3. Disconnect the electrical connector:S155 Lane Departure Warning Switch
    4. Ignition - On / Vehicle - In Service Mode
    5. Test for less than 1 V between the test points:Control circuit terminal 7@Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    6. Test for less than 2 ohms between the test points:Control circuit terminal 7@Component harness & Control circuit 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:S155 Lane Departure Warning Switch
    • Go to next step: If the component is On 
  12. Test or replace the component:B174W Frontview Camera - Windshield
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