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Tahoe / Yukon Service Manual

DTC C1304

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 C1304 Cruise/ETC/TCC Brake Signal 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 Performance
6311 Signal C1304 11 C1304 13 C1304 12 —

Circuit/System Description The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The K9 Body Control Module (BCM) provides low reference, signal, and reference voltage circuits to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will send a serial data message to the K219 Lighting Control Module requesting the brake lights on. The Lighting Control Module responds by apply battery voltage to the right and left stop lamp control circuits, and the center high mounted stop lamp control circuit. In addition to the serial data message from the BCM, the BCM also applies voltage to signal circuit 6311 to the Lighting Control Module and K20  Engine Control Module. This circuit informs the modules that the brake pedal is being applied. Diagnostic Aids Verify that the brake pedal position sensor is properly calibrated prior to performing Circuit/System Testing. Refer to Brake Pedal Position Sensor Calibration. Conditions for Running the DTC Battery voltage must be between 9–16 V. Brakes APPLIED. Conditions for Setting the DTC DTC C1304 11 The BCM detects a short to ground on signal circuit 6311. DTC C1304 12 The BCM detects a short to voltage on signal circuit 6311. DTC C1304 13 The BCM detects an open/high resistance on signal circuit 6311. Actions Taken When the DTC Sets The cruise control system is disabled. 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 Cruise Control Schematics 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

  1. Ignition/vehicle OFF, disconnect the X4 connector at the K219 Lighting Control Module.
  2. Connect a test lamp between signal circuit terminal 7 and ground, ignition ON/vehicle in service mode.
  3. Verify the test lamp turns ON and OFF while pressing and releasing the brake pedal. ⇒ If the test lamp is always OFF 3.1. Test circuit 6311 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. Test circuit 6311 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 3.3. Replace the K9 Body Control Module. ⇒ If the test lamp is always ON 3.1. Test circuit 6311 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 K9 Body Control Module. ⇓ If the test lamp turns ON and OFF
  4. A fault is not currently present and may be an intermittent condition. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Lighting Component Replacement Reference Control Module References