C1100 Code: ABS Pump Switch Circuit Failure
🟠 Moderate severity · drivable
Drivable — standard brakes still work — but ABS may be disabled, so drive cautiously and fix it soon.
What C1100 means
The switch inside the ABS hydraulic unit that confirms pump operation has failed. The ABS system can't verify the pump is running, so it may disable itself.
Symptoms
- ABS warning light on
- ABS disabled (no pulsing during hard stops)
Common causes
- most common: Faulty ABS pump switch
- common: Faulty ABS hydraulic unit
- common: Damaged wiring or connector
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Repair damaged switch wiring | Mechanic | $50–150 |
| Replace the ABS hydraulic unit | Mechanic | $400–1200 |
Frequently asked questions
Can I drive with a C1100 code?
Yes, regular brakes still work, but ABS may be disabled. Drive cautiously.
What is the most common cause of C1100?
A faulty ABS pump switch, often requiring replacement of the hydraulic unit.
How much does it cost to fix a C1100?
$50–$150 for wiring, or $400–$1,200 for a hydraulic unit.
Related codes
C1095
C1095 Code: ABS Hydraulic Pump Motor Circuit Failure
C1238C1238 Code: ABS Hydraulic Pressure Differential Switch Input Circuit Failure
C1096C1096 Code: ABS Hydraulic Pump Motor Circuit Open
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.