LEMON Manuals: Even more car manuals for everyone
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 B1998 or B1999 >> 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 B1998

  1. Ignition OFF, exterior lamps OFF, disconnect the connector at the E4C Daytime Running Lamp - Left.
  2. Connect a test lamp between control circuit terminal 3 and ground circuit terminal 1.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Left Front Turn Signal Command ON and OFF with a scan tool.
    • If the test lamp is always ON 
    1. Test circuit 1314 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 1314 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 1314 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 E4C Daytime Running Lamp - Left.

DTC B1999

  1. Ignition OFF, exterior lamps OFF, disconnect the connector at the E4D Daytime Running Lamp - Right.
  2. Connect a test lamp between control circuit terminal 3 and ground circuit terminal 1.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Right Front Turn Signal Command ON and OFF with a scan tool.
    • If the test lamp is always ON 
    1. Test circuit 1315 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 1315 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 1315 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 E4D Daytime Running Lamp - Right.
scientia non olet · About LEMON Manuals