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 C012B 01: High Pressure Accumulator Pressure Sensor Short to BatteryDTC C12B7: High Pressure Accumulator Pressure Sensor Short to Battery
DTC C012B 06: High Pressure Accumulator Pressure Sensor Short to Ground or Open
DTC C12B6: High Pressure Accumulator Pressure Sensor Short to Ground or Open
DTC C012B 0F: High Pressure Accumulator Pressure Sensor Erratic
DTC C12B8: High Pressure Accumulator Pressure Sensor Erratic
Circuit/System Description
The high pressure accumulator is attached to the brake pressure modulator valve and provides up to 2500 psi for use in apply the brakes. The electronic brake control module (EBCM) uses input from the high pressure accumulator sensor for more accurate control during braking and vehicle stability enhancement system (VSES) event.The high pressure accumulator sensor is internal to the brake pressure modulator valve (BPMV).
Conditions for Running the DTC
| • | Ignition ON. |
| • | Ignition voltage is greater than 10 volts. |
Conditions for Setting the DTC
C012B 01 or C12B7
A short to battery is detected on the sensor signal circuit.
C012B 06 or C12B6
A short to ground or open is detected on signal circuit.
C012B OF or C12B8
Signal is erratic and changes faster than physically allowed.
Action Taken When the DTC Sets
| • | The EBCM disables the ABS and 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
| • | 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
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Verify that DTC C012B, C12B7, C12B6, C12B8 is not set.
| ⇒ | If DTC is set replace EBCM/brake pressure modulator valve (BPMV) assembly. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for EBCM replacement, setup, and programming |
