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 B1A75 >> 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 B1A75

  1. Ignition OFF, exterior lamps OFF, disconnect the E6 Center High Mounted Stop Lamp.
  2. Connect a test lamp between ground circuit terminal 1 and control circuit terminal 2.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Center High Mounted Stop Lamp ON and OFF with the scan tool.
    • If the test lamp is always ON 
    1. Test circuit 820 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 turns is always OFF 
    1. Test circuit 2450 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 820 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 820 for a 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 E6 Center High Mounted Stop Lamp.
scientia non olet · About LEMON Manuals