What Does C1250 Mean?
The ABS control module has detected a circuit failure in the left rear ABS inlet valve coil. The inlet valve controls the application of brake pressure during ABS events — when energized, it blocks additional pressure from reaching the wheel cylinder. A coil failure means the module cannot isolate brake pressure at the left rear wheel during anti-lock braking.
Safety Warning
Left rear ABS inlet valve is inoperative. The ABS cannot properly isolate brake pressure at this wheel, compromising anti-lock braking performance. Repair before driving in poor conditions.
Common Causes
40%
Failed inlet valve coil winding inside the ABS hydraulic control unit from thermal cycling or internal short
25%
Broken solder joint or cracked circuit board trace on the inlet valve driver inside the ABS module
20%
Corroded internal connector between the ABS electronic module and hydraulic modulator
15%
Contamination inside the modulator from degraded brake fluid damaging valve coil insulation
Diagnostic Steps
1
Step 1: Measure left rear inlet valve coil resistance at the ABS module connector (typical 3-6 ohms). Compare to the right rear inlet valve. Significantly different readings point to the failed coil.
2
Step 2: Check for short to ground and short to battery on both inlet valve circuit wires at the module connector.
3
Step 3: Inspect the ABS module-to-modulator interface for signs of brake fluid leakage, corrosion, or seal deterioration.
4
Step 4: Command the left rear inlet valve using a bidirectional scan tool. Listen for an audible solenoid click confirming mechanical valve movement.
5
Step 5: If the coil tests bad, replace the ABS hydraulic modulator assembly. Perform a complete ABS bleed, clear codes, and test drive to verify proper ABS cycling.
Estimated Repair Cost
$300 - $1,200
Parts + labor, varies by vehicle and location
The ABS control module has detected a circuit failure in the left rear ABS inlet valve coil. The inlet valve controls the application of brake pressure during ABS events — when energized, it blocks additional pressure from reaching the wheel cylinder. A coil failure means the module cannot isolate b...
The most common cause of C1250 (ABS Inlet Valve Coil LR Circuit Failure) is: Failed inlet valve coil winding inside the ABS hydraulic control unit from thermal cycling or internal short
Typical repair costs for C1250 range from $300 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Left rear ABS inlet valve is inoperative. The ABS cannot properly isolate brake pressure at this wheel, compromising anti-lock braking performance. Repair before driving in poor conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1250 to identify the root cause.
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Quick Info
Category
Chassis
System
Anti-lock Brake System (ABS)
Difficulty
Type
Manufacturer
Recommended Tools
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