DTC C012E or C12FE. GMC Truck Sierra Denali 2009

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2009 🢒 Sierra Denali 🢒 Brakes 🢒 Antilock Brake System - Hybrid (HP2) 🢒 DTC C012E or C12FE

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 C012E 00: Boost Loss Fault

DTC C12FE: Boost Loss Pressure Loss

The electronic brake control module (EBCM) uses input from the boost pressure sensor for more accurate control during brake and vehicle stability enhancement system (VSES) event. The boost pressure sensor is internal to the brake pressure modulator valve (BPMV). The boost control function will keep operating amongst conditions that cause the boost pressure to be limited to less than commanded. The boost control continues to apply until the boost pressure available is no greater than the MC pressure the driver is applying.

Conditions for Running the DTC

•	The ignition is ON.

•	Ignition voltage is greater than 10 volts.

•	Transmission in Park

Conditions for Setting the DTC

•	Boost pressure command greater than boost pressure +1500 kpa (217 psi) for 250 ms.

•	Master cylinder pressure greater than boost pressure -200 kpa (29 psi) for 250 ms.

•	Accumulator pressure greater than 16,000 kpa (2320 psi) for 250 ms.

•	DTCs C12BC, C12BD, C12BE, C128A, C128D, C127D, C12E4, C1255, C1256, C126E, C123C, or C127C not set.

Action Taken When the DTC Sets

•	The EBCM disables the ABS/traction control system (TCS)/vehicle stability enhancement system (VSES) for the duration of the ignition cycle.

•	A DIC message and/or a warning indicator may be displayed.

Conditions for Clearing the DTC

217 psi)

•	The condition for setting the DTC is no longer present.

•	The EBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.

Reference Information

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

With scan tool, verify that the accumulator pressure is greater than the master cylinder pressure.

⇒	If the accumulator pressure is less than master cylinder pressure, refer to Hydraulic Brake System Diagnosis

Replace EBCM/ Brake Pressure Modulator Valve (BPMV) assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Brake Pressure Modulator Valve Replacement

•	Control Module References for EBCM replacement, setup, and programming