What Does C1110 Mean?
This code indicates that the ABS control module has detected an abnormal electrical condition in the power relay coil circuit that energizes the main ABS hydraulic pump and solenoid valves. The ABS module continuously monitors the relay coil for proper resistance, voltage, and current flow, and has identified either an open circuit, short circuit, or excessive resistance preventing the relay from operating correctly. When this fault occurs, the ABS system typically defaults to conventional braking only, disabling anti-lock functionality.
Common Causes
35%
Failed ABS power relay with open or shorted coil windings
25%
Corroded or damaged relay socket terminals with high resistance connection
20%
Open circuit or damaged wiring between ABS module and relay coil
12%
Poor ground connection at ABS relay ground circuit
8%
Internal ABS control module relay driver circuit failure
Diagnostic Steps
1
Step 1: Visually inspect the ABS power relay location (typically in engine bay fuse/relay box) for corrosion, bent pins, melted housing, or moisture intrusion. Remove relay and inspect socket terminals for burning or corrosion damage.
2
Step 2: Using a digital multimeter, measure resistance across the relay coil terminals (typically pins 85 and 86). Expected reading should be 70-120 ohms for most automotive relays. Infinite resistance indicates open coil; near-zero indicates shorted coil.
3
Step 3: With ignition on and relay removed, measure voltage at the relay socket power supply terminal (typically pin 86) - should read battery voltage (12-14V). Then check for continuity between the control terminal (typically pin 85) and the ABS module connector pin specified in wiring diagram.
4
Step 4: Locate and inspect the relay coil ground circuit, verify less than 0.5 ohms resistance to battery negative. Check for voltage drop test: connect voltmeter between ground terminal and battery negative, command relay on with scan tool (active test if available), voltage drop should be less than 0.1V.
5
Step 5: If all external circuits test normal, substitute a known-good relay and clear codes. Road test vehicle to verify ABS operation. If code returns immediately with good relay and verified circuits, ABS module internal relay driver is likely failed and module replacement required.
Estimated Repair Cost
$80 - $850
Parts + labor, varies by vehicle and location
This code indicates that the ABS control module has detected an abnormal electrical condition in the power relay coil circuit that energizes the main ABS hydraulic pump and solenoid valves. The ABS module continuously monitors the relay coil for proper resistance, voltage, and current flow, and has ...
The most common cause of C1110 (ABS Power Relay Coil Circuit Failure) is: Failed ABS power relay with open or shorted coil windings
Typical repair costs for C1110 range from $80 to $850, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle remains safe to drive as normal braking function is retained, but anti-lock braking capability will be disabled, increasing stopping distances on slippery surfaces and during emergency braking. Repair should be completed promptly, especially before winter or wet weather conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1110 to identify the root cause.
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Quick Info
Category
Chassis
System
Anti-lock Brake System (ABS)
Difficulty
Type
Manufacturer
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