Corroded or loose ground connection at the pump motor mounting point; Broken or chafed ground wire between the pump motor and chassis; Failed pump motor ground terminal or internal motor ground fault; Damaged connector at the ABS pump motor or control module; Open circuit inside the ABS control module ground path; Corrosion in the wiring harness due to water intrusion

DTC codes / C02xx · Brakes, steering and suspension / C0252

C0252Pump Motor Ground Circuit Open

Q: What does code C0252 mean?

Pump Motor Ground Circuit Open. C0252 indicates that the anti-lock brake system (ABS) control module has detected an open circuit in the ground path for the ABS pump motor. The module monitors the voltage on the pump motor ground circuit and sets this code when the expected ground reference is missing, which prevents the pump from operating during ABS activation.

C0252 indicates that the anti-lock brake system (ABS) control module has detected an open circuit in the ground path for the ABS pump motor. The module monitors the voltage on the pump motor ground circuit and sets this code when the expected ground reference is missing, which prevents the pump from operating during ABS activation.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

ABS warning light illuminated on the dashboard
Traction control or stability control warning light may also be on
Often no symptoms besides the warning light
ABS may not activate during hard braking or slippery conditions
Pump motor may not run during self-test, sometimes causing a brief noise or no noise at all

Common causes, most likely first

Corroded or loose ground connection at the pump motor mounting point
Broken or chafed ground wire between the pump motor and chassis
Failed pump motor ground terminal or internal motor ground fault
Damaged connector at the ABS pump motor or control module
Open circuit inside the ABS control module ground path
Corrosion in the wiring harness due to water intrusion

How to diagnose and fix it

Inspect and clean the pump motor ground connection at the chassis, checking for tightness and corrosion
Perform a voltage drop test on the ground circuit while cranking or activating the pump to confirm excessive resistance
Disconnect the pump motor connector and check for continuity between the motor ground terminal and chassis ground
Inspect the wiring harness for physical damage, chafing, or corrosion, especially near the pump and module
Check the ABS control module connector for loose pins or corrosion and verify ground circuit integrity to the module
If the ground circuit is intact, test the pump motor itself for an open internal ground; replace the motor or module as needed
Clear the code and perform a road test to verify the repair and ensure the ABS self-test completes

Ground Circuit Faults Often Misdiagnosed

A loose or corroded ground bolt at the pump motor is a frequent cause that is often overlooked because the connection looks tight visually.
The code can set intermittently due to vibration or temperature changes, so a wiggle test of the ground wire while monitoring live data is valuable.
Some vehicles use a shared ground point for the ABS pump and other systems, so a fault elsewhere can cause this code without a problem in the pump circuit itself.
Replacing the ABS pump motor or module without first verifying the ground circuit integrity can lead to repeat failures and unnecessary expense.
The ABS control module may set this code if the pump motor ground is open only during activation, so a static continuity test may not reveal the fault.

Can I keep driving with C0252?

The vehicle remains safe to drive under normal conditions because the base brakes still function, but avoid situations that require ABS activation such as hard braking or slippery surfaces. Have the fault diagnosed promptly to restore full ABS and stability control function.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.