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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 224 (Lighting System - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC B1996 or B1997 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

DTC B1996

  1. Ignition OFF, exterior lamps OFF, disconnect the connector at the E13LA Front Headlamp - Left.
  2. Connect a test lamp between control circuit terminal 2 and ground circuit terminal 1.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Left Low Beam Command ON and OFF with a scan tool.
    • If the test lamp is always ON 
    1. Test circuit 712 for a short to voltage
      • If a short to voltage is found, repair the fault.
      • Go to next step: If a short to voltage is not found, replace the K219 Lighting Control Module.
    • If the test lamp is always OFF 
    1. Test circuit 550 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit or ground connection.
      • Go to next step: If an open/high resistance is not found
    2. Test circuit 712 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit
      • Go to next step: If an open/high resistance is not found
    3. Test circuit 712 for short to ground
      • If a short to ground is found, repair the fault on the circuit
      • Go to next step: If a short to ground is not found
    4. Replace the K219 Lighting Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Replace the E13LA Front Headlamp - Left.

DTC B1997

  1. Ignition OFF, exterior lamps OFF, disconnect the connector at the E13RA Front Headlamp - Right.
  2. Connect a test lamp between control circuit terminal 2 and ground circuit terminal 1.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Right Low Beam Command ON and OFF with a scan tool.
    • If the test lamp is always ON 
    1. Test circuit 312 for a short to voltage
      • If a short to voltage is found, repair the fault.
      • Go to next step: If a short to voltage is not found, replace the K219 Lighting Control Module.
    • If the test lamp is always OFF 
    1. Test circuit 650 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit or ground connection.
      • Go to next step: If an open/high resistance is not found
    2. Test circuit 312 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit
      • Go to next step: If an open/high resistance is not found
    3. Test circuit 312 for short to ground
      • If a short to ground is found, repair the fault on the circuit
      • Go to next step: If a short to ground is not found
    4. Replace the K219 Lighting Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Replace the E13RA Front Headlamp - Right.
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