C0274

DTC C0274

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC C0274
- ABS Motor Relay Shorted

Circuit/System Description

The pump motor relay is part of the electronic brake control module (EBCM) on vehicles without traction control. The pump motor relay is located in the Antilock Brake System (ABS) relay block on vehicles with traction control. The EBCM turns ON and OFF the pump motor relay as deemed necessary in order to activate the pump motor. The pump motor modulates brake hydraulic pressure during an ABS stop.

Conditions for Running the DTC

Ignition is in the ON position

Conditions for Setting the DTC

The EBCM detects an open in the pump motor circuitry.

Action Taken When the DTC Sets

* The ABS is disabled.
* The ABS warning indicator turns ON.
* The traction control and vehicle stability control (VSC) is disabled, if equipped.
* The VSC warning indicator turns ON, if equipped.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Reference Information
Schematic Reference

Antilock Brake System Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit Verification

Ignition ON, perform the Pump Motor Test with a scan tool and listen/feel the Pump Motor turn ON and OFF.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Test for less than 1 ohm between the terminals 1, 13 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, check for 11-14V between terminals, 12, 24, 34 and ground.

• If the voltage is not as specified, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BPMV.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Brake Pressure Modulator Valve Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming