What Does C1111 Mean?
This code indicates the ABS control module has detected an open circuit in the power relay coil that supplies power to the Anti-lock Brake System. The ABS module energizes this relay coil to power up the hydraulic pump motor and solenoid valves needed for ABS operation. An open circuit means electricity cannot flow through the relay coil, preventing the ABS system from activating and leaving only conventional braking available.
Common Causes
45%
Failed ABS power relay with open coil winding internally
30%
Broken or corroded wiring between ABS module and relay coil terminals
15%
Loose or corroded relay socket connection or damaged relay mounting base
10%
Failed ABS control module unable to provide ground or power to relay coil
Diagnostic Steps
1
Step 1: Locate the ABS power relay (typically in engine compartment fuse/relay box) and perform visual inspection for corrosion, burnt contacts, or damaged terminals. Remove relay and inspect socket for pushed-back pins or corrosion.
2
Step 2: Using a digital multimeter, test the removed relay coil resistance across the control terminals (typically 70-120 ohms for most relays). If reading shows infinite resistance (OL), relay coil is open and relay must be replaced.
3
Step 3: With relay removed and ignition on, check for battery voltage at the relay socket power supply terminal using multimeter. Then check for ground signal from ABS module at the relay coil control terminal when ABS system attempts to activate.
4
Step 4: Inspect wiring harness between ABS module and relay socket for cuts, chafing, or damaged insulation. Check connector terminals at both ends for corrosion, bent pins, or loose connections using multimeter continuity testing.
5
Step 5: Install known-good relay and clear codes. Road test vehicle while monitoring for code return. Verify ABS warning lamp extinguishes and ABS system functions properly during controlled braking test.
Estimated Repair Cost
$75 - $350
Parts + labor, varies by vehicle and location
This code indicates the ABS control module has detected an open circuit in the power relay coil that supplies power to the Anti-lock Brake System. The ABS module energizes this relay coil to power up the hydraulic pump motor and solenoid valves needed for ABS operation. An open circuit means electri...
The most common cause of C1111 (ABS Power Relay Coil Open Circuit) is: Failed ABS power relay with open coil winding internally
Typical repair costs for C1111 range from $75 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive with conventional braking, but ABS functionality is disabled which may result in wheel lockup during hard braking or slippery conditions. Repair soon to restore full braking system safety features, especially important in adverse weather or emergency stops.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1111 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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