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Tahoe / Yukon Service Manual

Hands-Free Liftgate Sensor Lamp Malfunction

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. Diagnostic Fault Information

Circuit Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
2066 Control B1A4F 11 1 1 —
1. Rear Closure Hands Free Lamp Malfunction

Scan Tool Functions K9 Body Control Module – Control Functions – Exterior Lighting

Control Function Description
Hands-Free Sensor Lamp Command This control function will control the hands-free sensor lamp ON/OFF

Circuit/System Description The rear closure hands-free lamp illuminates the vehicle’s brand logo in the area where the sensor for the foot activated liftgate actuator is located for hands-free liftgate operation. When the keyless entry transmitter is operated to either the lock or unlock functions, the rear closure hands-free lamp is commanded on by the K9 Body Control Module. The rear closure hands-free lamp will display the image of the vehicle’s brand logo on the ground directly under the center of the rear bumper. Diagnostic Aids Clean the lens of the hands-free liftgate sensor lamp with a soft, dampened cloth before diagnosing the electrical system. Battery voltage must be above 11.5 V for approach lighting to illuminate. Approach lighting will not illuminate if a RKE transmitter Has been left within approximately 5 m (15 ft) of the liftgate for several minutes. Approach lighting will not illuminate if a RKE transmitter has not been detected for more than 14 days. If there are multiple Keyless Entry faults in addition to approach lighting, refer to: Keyless Entry System Malfunction Reference Information Schematic Reference Exterior Lights Schematics Liftgate Schematics Connector End View Reference Master Electrical Component List Description and Operation Exterior Lighting Systems Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Circuit/System Verification

  1. Ignition on/vehicle in service mode
  2. Verify there are no keyless entry system DTCs set. ⇒ If keyless entry DTCs are set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If no keyless entry DTCs are set
  3. Verify the rear closure hands free lamp turns ON and OFF when commanding the Hands-Free Sensor Lamp Command ON and OFF with a scan tool. ⇒ If the hands-free liftgate sensor lamp does not turn ON and OFF Refer to Circuit/System Testing ⇓ If the hands-free liftgate sensor lamp turns ON and OFF
  4. Verify the vehicle locks and unlock with the RKE Transmitter. ⇒ If the vehicle does not lock/unlock Refer to: Keyless Entry System Malfunction ⇓ If the vehicle does lock/unlock
  5. A fault is not currently present and may be an intermittent condition. Circuit/System Testing
  6. Ignition/vehicle OFF, disconnect the E72 Rear Closure Hands Free Lamp.
  7. Verify a test lamp illuminates between ground circuit terminal 2 and B+. ⇒ If the test lamp does not illuminate 2.1. Repair the open/high resistance on the ground circuit or ground connection. ⇓ If the test lamp illuminates
  8. Connect a test lamp between control circuit terminal 1 and ground, ignition on/vehicle in service mode.
  9. 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 OFF 4.1. Test circuit 2066 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 4.2. Test circuit 2066 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 4.3. Replace the K9 Body Control Module. ⇒ If the test lamp is always ON 4.1. Test circuit 2066 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 4.2. Replace the K9 Body Control Module. ⇓ If the test lamp turns ON and OFF
  10. Replace the E72 Rear Closure Hands Free Lamp. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Lighting Component Replacement Reference Control Module References for BCM replacement, programming, and setup