Diagnostic Instructions
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 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
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
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
- Ignition OFF, disconnect the harness connector at the EBCM.
- 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. |
- 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
after completing the diagnostic procedure.
