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Tahoe / Yukon Service Manual

DTC B19BA

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 Descriptor DTC B19BA Exterior Courtesy Lamp Control Refer to Symptom Byte List for symptom byte information. Diagnostic Fault Information

Circuit Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
1430 Control B19BA 11 1 1 —
1850 Ground — 1 — —
1. Rear Compartment Lamp Malfunction

Circuit/System Description When the K9 Body Control Module (BCM) receives a rear compartment latch open input from the rear compartment lid latch, the BCM applies pulse width modulated (PWM) voltage to control circuit 1430 illuminating the rear cargo courtesy lamp. In the event that the rear cargo courtesy lamp were to remain illuminated for more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the rear compartment lamp control circuit to prevent total battery discharge. Conditions for Running the DTC Battery voltage must be between 9-16 V. Conditions for Setting the DTC The BCM detects a short to ground on circuit 1430. Actions Taken When the DTC Sets The rear cargo courtesy lamps are inoperative. Conditions for Clearing the DTC The condition responsible for setting the DTC no longer exists. A history DTC will clear once 40 consecutive malfunction-free ignition cycles have occurred. Reference Information Schematic Reference Interior Lights Schematics Connector End View Reference Master Electrical Component List Description and Operation Interior 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 Testing

  1. Ignition/vehicle OFF, disconnect the X7 connector at the K9 Body Control Module.
  2. Connect a 3 A fused jumper wire between control circuit terminal 18 and B+.
  3. Verify the E8SR Cargo Center Courtesy Lamp turns ON and OFF when connecting and disconnecting the jumper wire. ⇒ If the cargo lamp is always OFF and the 3 A fuse is OK 3.1. Ignition/vehicle OFF, disconnect the connector at the E8SR Cargo Center Courtesy Lamp. 3.2. Verify a test lamp illuminates between ground circuit terminal 3 and B+. ⇒ If the test lamp does not illuminate, repair the open/high resistance on circuit 1850 or ground connection. ⇓ If the test lamp illuminates. 3.3. Test circuit 1430 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. 3.4. Replace the E8SR Cargo Center Courtesy Lamp. ⇒ If the cargo lampis always OFF and the 3 A fuse is open 3.1. Test circuit 1430 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. 3.2. Replace the E8SR Cargo Center Courtesy Lamp. ⇒ If the cargo lamp is always ON 3.1. Test circuit 1430 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. 3.2. Replace the E8SR Cargo Center Courtesy Lamp. ⇓ If the cargo lamp turns ON and OFF
  4. Replace the K9 Body Control Module. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Lighting Component Replacement Reference Control Module References for BCM replacement, programming, and setup