C0901

DTC C0901

DTC Descriptor

DTC C0901
- Device 2 Voltage Low

Diagnostic Fault Information

Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Diagnostic System Check - Vehicle

Circuit/System Description

The electronic brake control module (EBCM) monitors the ignition 1 voltage (IGN1) level available for system operation. A low voltage condition prevents the system from operating properly.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

* Ignition 1 (IGN1) voltage to EBCM is less than 6.5 volts for 7 seconds.
* Vehicle speed is greater than 3 km/h (2 mph).

Action Taken When the DTC Sets

Brake Warning indicator turns ON.

Conditions for Clearing the DTC

* The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Circuit/System Testing

1. Measure and record the voltage at the battery terminals.

• If the battery voltage is low, diagnose the starting and charging system.

2. Disconnect the EBCM connector and turn the ignition ON. At the EBCM harness connector, measure voltage on the IGN1 circuit.

• If the voltage is more than one volt less than battery positive voltage, repair open or high resistance in IGN1 circuit.
• If the battery positive voltage and IGN1 voltage is within 1-volt, repair open or high resistance in the EBCM ground circuits.
• If no electrical faults are present, replace the EBCM/brake pressure modulator valve (BPMV) replacement.

Repair Instructions

Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Refer to Programing and Relearning for EBCM and BPMV replacement, setup, and programming. Programming and Relearning