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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 B356A >> 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. Verify a test lamp turns On between the test points:Ground circuit terminal 8 & B+
    • If the test lamp does not turn On 
    1. Test for less than 2 ohms between the test points:Ground circuit terminal 8 & Ground Connection
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If the test lamp turns On 
  4. Connect the electrical connector:S155 Lane Departure Warning Switch
  5. Disconnect the electrical connector:B174W Frontview Camera - Windshield
  6. Test for less than infinite resistance between the test points: Signal circuit terminal 10 & Ground.
    • If infinite resistance 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:S155 Lane Departure Warning Switch
    3. Test for less than 2 ohms between the test points:Signal circuit terminal 4@Component harness & Signal circuit terminal 10@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 less than infinite resistance 
  7. Connect a DMM between the test points:Signal circuit terminal 10 & Ground
  8. Press and release the switch:Lane Departure Warning Switch

    Verify resistance on the DMM changes when pressing and releasing the switch.

    • If resistance does not change 
    1. Disconnect the electrical connector:S155 Lane Departure Warning Switch
    2. Test for less than 1 V between the test points:Signal circuit terminal 4@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
    3. Test for infinite resistance between the test points:Signal circuit terminal 4@Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If less than 2 ohms - Replace the component:S155 Lane Departure Warning Switch
    • Go to next step: If resistance changes 
  9. Test or replace the component:B174W Frontview Camera - Windshield
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