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Tahoe / Yukon Service Manual

DTC B19A5

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. DTC Descriptors DTC B19A5 49 Rear Closure Hands Free Module Internal Malfunction DTC B19A5 54 Rear Closure Hands Free Missing Calibration DTC B19A5 55 Rear Closure Hands Free Not Configured DTC B19A5 A2 Rear Closure Hands Free System Voltage Low DTC B19A5 A3 Rear Closure Hands Free System Voltage High Circuit/System Description The power liftgate has a feature that detects the motion of a foot under the rear fascia, this allows the operator to open the liftgate when his or her hands are full of packages. As an indicator that the action has been properly preformed, the rear closure hands free module will send a serial data message to the rear gate module to command the liftgate to release and power open and the rear gate module will send a serial data message to the lighting control module to command the tail lights to flash 3 times Conditions for Running the DTC Battery voltage is between 9–16 V. Conditions for Setting the DTC B19A5 49 An internal malfunction has been detected by the rear gate module B19A5 54 The rear gate module detects the calibration files in the rear closure hands free module does not match the calibration files contained within the rear gate module. B19A5 55 The rear gate module detects the rear closure hands free module has not been configured B19A5 A2 The rear gate module detects low voltage in the rear closure hands free module B19A5 A3 The rear gate module detects high voltage in the rear closure hands free module Action Taken When the DTC Sets The hands-free feature will be inoperative Conditions for Clearing the DTC B19A5 49, B19A5 54, B19A5 55 The rear closure hands free module must be replaced before DTC can be cleared B19A5 A2, B19A5 A3 A current DTC will clear when the diagnostic runs and passes. A history DTC will clear after 40 consecutive malfunction-free ignition cycles. Reference Information Schematic Reference Liftgate Schematics Connector End View Reference Master Electrical Component List Description and Operation Liftgate 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 DTC B19A5 49, B19A5 54, B19A5 55 is not set. ⇒ If the DTC is set Replace the component: K171 Rear Closure Hands Free Module ⇓ If the DTC is not set
  3. Verify DTC B19A5 A2 is not set. ⇒ If the DTC is set Refer to: Charging System Test ⇓ If the DTC is not set
  4. Verify DTC B19A5 A3 is not set. ⇒ If the DTC is set Refer to: Charging System Test ⇓ If the DTC is not set
  5. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair Rear Closure Hands Free Module Replacement Control Module References for rear closure hands free module replacement, programming and setup