C0110
Pump Motor Circuit Malfunction
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Code C0110 indicates that the Electronic Brake Control Module (EBCM) has detected a problem with the ABS pump motor circuit. The ABS pump motor is responsible for restoring brake fluid pressure in the hydraulic modulator during anti-lock braking and traction control events. The EBCM supplies ground to the motor and monitors its feedback voltage to detect stalling, binding, or open circuit conditions.
When this code is set, the ABS, traction control, and stability control systems will all be disabled. The regular braking system continues to function, but you lose all electronic braking aids. In some cases, you may hear the pump motor running continuously or making a grinding noise, which indicates it may be stuck or the relay is malfunctioning.
This should be diagnosed within the week. Start by inspecting the 2-wire pump motor connector for corrosion — this is a common and inexpensive fix. You can also check the pump motor resistance (should be 0.3 to 1.0 ohms across the motor terminals). If the connector and wiring are clean, the pump motor or EBCM itself may need replacement, which can be a more costly repair ranging from $500 to $1,200 at a shop.
Severity
Symptoms
- •ABS warning light illuminated on dashboard
- •Brake warning light may also be on
- •ABS pump motor runs continuously or not at all
- •Traction control and stability control systems disabled
- •Brake pedal feels hard or unresponsive during ABS events
- •Grinding or buzzing noise from ABS module area
Likely Causes
The pump motor inside the ABS hydraulic modulator can wear out over time or fail electrically, causing it to stall, run continuously, or not operate when commanded.
The 2-wire pump motor connector is prone to corrosion, especially in salt-belt regions. Corroded pins create high resistance that prevents the motor from operating properly.
The EBCM supplies ground to the pump motor and uses an internal relay for battery positive voltage. Failure of this relay or the monitoring circuitry triggers the code.
If the brake fluid reservoir is low, the pump can run dry or cavitate, causing the EBCM to detect abnormal feedback voltage from the pump motor.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Clean corroded pump motor connector pins and apply dielectric grease
- Replace the ABS pump motor
- Replace the EBCM if internal relay or circuit failure is confirmed
- Replace the entire ABS modulator and EBCM assembly
- Check and top off brake fluid to proper level