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Tahoe / Yukon Service Manual

DTC B19A1 or B19A2

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 B19A1 Left Rear Park Lamp Control DTC B19A2 Right Rear Park Lamp Control Refer to Symptom Byte List for symptom byte information. Diagnostic Fault Information

Circuit Circuit Function Short to Ground Open/Hig Resistance h Short to Voltage Signal Performan
6993 Control B19A1 11 1 1 —
6995 Control B19A2 11 1 1 —
1950 Ground — 1 — —
2050 Ground — 1 — —
1. Park Lamps Malfunction

Scan Tool Functions K219 Lighting Control Module – Control Functions – Exterior Lighting

Control Function Description
Left Tail Lamp Command This control function will control the left rear park lamp ON/OFF
Right Tail Lamp Command This control function will control the right rear park lamp ON/OFF

Circuit/System Description When the headlamp switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the K9 Body Control Module (BCM). The BCM responds by sending a serial data message to the K219 Lighting Control Module. The Lighting Control Module responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps. Conditions for Running the DTC Battery voltage must be between 9–16 V Battery voltage must be between 9 16 V. Park lamps ON. Conditions for Setting the DTC DTC B19A1 11 The Lighting Control Module detects a short to ground on control circuit 6993. DTC B19A2 11 The Lighting Control Module detects a short to ground on control circuit 6995. Actions Taken When the DTC Sets The rear park lamps will not operate when the park lamps are ON. 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 Exterior Lights 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 Testing DTC B19A1

  1. Ignition OFF, exterior lamps OFF, disconnect the E42L Rear Body Structure Stop Lamp - Left.
  2. Verify a test lamp illuminates between ground circuit terminal 1 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
  3. Connect a test lamp between the control circuit terminal 3 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the Left Tail Lamp Command ON and OFF with a scan tool. ⇒ If the test lamp is always OFF 4.1. Test circuit 6993 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 6993 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 K219 Lighting Control Module. ⇒ If the test lamp is always ON 4.1. Test circuit 6993 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 K219 Lighting Control Module. ⇓ If the test lamp turns ON and OFF
  5. Replace the E42L Rear Body Structure Stop Lamp - Left. DTC B19A2
  6. Ignition OFF, exterior lamps OFF, disconnect the E42R Rear Body Structure Stop Lamp - Right.
  7. Verify a test lamp illuminates between ground circuit terminal 1 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 the control circuit terminal 3 and ground, ignition ON.
  9. Verify the test lamp turns ON and OFF when commanding the Right Tail Lamp Command ON and OFF with a scan tool. ⇒ If the test lamp is always OFF 4.1. Test circuit 6995 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 6995 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 K219 Lighting Control Module. ⇒ If the test lamp is always ON 4.1. Test circuit 6995 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 K219 Lighting Control Module. ⇓ If the test lamp turns ON and OFF
  10. Replace the E42R Rear Body Structure Stop Lamp - Right. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Lighting Component Replacement Reference Control Module References for BCM replacement, programming, and setup