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 B1A4F >> 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 B1A4F

  1. Ignition OFF, exterior lamps OFF, disconnect the connector at the E72 Rear Closure Hands Free Lamp.
  2. Connect a test lamp between control circuit terminal 1 and ground circuit terminal 2.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Hands-Free Sensor Lamp Command ON and OFF with a scan tool.
    • If the test lamp is always ON 
    1. Test circuit 2066 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 K9 Body Control Module.
    • If the test lamp is always OFF 
    1. Test circuit 2550 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 2066 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 2066 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 K9 Body Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Replace the E72 Rear Closure Hands Free Lamp.
scientia non olet · About LEMON Manuals