ABS Pump Motor Circuit Short to Ground
The C0120 code means the vehicle's onboard diagnostic system has detected: ABS Pump Motor Circuit Short to Ground. This is a critical severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $200 - $1200 (parts and labor)
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Common Symptoms
- ABS warning light on
- ABS fuse blows repeatedly
- Burning smell from ABS module area
- Complete loss of ABS function
- Traction and stability control lights on
Probable Causes (Ranked by Likelihood)
- Short circuit in ABS pump motor winding Very High
- Chafed wiring contacting ground High
- Water intrusion into ABS module connector Moderate
- Damaged ABS pump motor relay causing short Moderate
- ABS control module internal short Low
Step-by-Step Diagnostic Procedure
-
Check the ABS pump motor fuse -- if blown, there is likely a short circuit
-
Disconnect the pump motor connector and measure resistance to ground -- should be infinite
-
Inspect all wiring in the pump motor circuit for chafing against the frame or body
-
Look for water damage or corrosion at the ABS module connector
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Test pump motor in isolation to determine if the short is in the motor or wiring
Frequently Asked Questions
Why does my ABS fuse keep blowing?
A repeatedly blown ABS fuse is a strong indicator of a short to ground in the pump motor circuit. The short draws excessive current and blows the fuse as a safety measure. Do not keep replacing the fuse without finding the short.
Can water damage cause a C0120 code?
Yes. Water intrusion into the ABS module connector or pump motor is a common cause. Driving through deep water or pressure washing the engine bay can introduce moisture that creates a short circuit.
Is a short to ground dangerous?
A short to ground can cause overheating in the wiring and potentially start a fire if the fuse does not blow. Do not bypass the fuse. Repair the short circuit before restoring ABS function.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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