What Does C1252 Mean?
The ABS control module has detected a short to battery voltage on the left rear ABS inlet valve coil circuit. Unwanted battery voltage is present on the valve driver circuit, which may cause the inlet valve to remain energized and block brake pressure application to the left rear wheel. This represents both an ABS functional failure and a potential electrical safety concern.
Safety Warning
A continuously energized inlet valve could block brake fluid pressure to the left rear wheel, causing reduced braking on that corner. This is a critical safety concern requiring immediate repair.
Common Causes
35%
Internal wiring short to a powered circuit inside the ABS module housing
25%
Shorted valve driver transistor on the ABS module circuit board applying constant battery voltage
25%
Valve coil winding insulation failure allowing contact with a powered conductor inside the modulator
15%
Moisture or contamination creating a conductive bridge to a battery voltage source
Diagnostic Steps
1
Step 1: Separate the ABS module from the hydraulic modulator. With key on, measure voltage on the inlet valve coil wires at the module connector. No battery voltage should be present unless commanded.
2
Step 2: With everything disconnected and key off, check for short to battery by measuring resistance from each valve wire to the battery positive terminal at the fuse box.
3
Step 3: Inspect the ABS module circuit board for burnt or darkened components near the left rear inlet valve driver, indicating a shorted transistor.
4
Step 4: Check the modulator valve coil insulation by measuring resistance from each coil terminal to any accessible power rail.
5
Step 5: Replace the component with the short. After repair, clear codes and perform bidirectional testing of all ABS valves to verify proper operation.
Estimated Repair Cost
$300 - $1,200
Parts + labor, varies by vehicle and location
The ABS control module has detected a short to battery voltage on the left rear ABS inlet valve coil circuit. Unwanted battery voltage is present on the valve driver circuit, which may cause the inlet valve to remain energized and block brake pressure application to the left rear wheel. This represe...
The most common cause of C1252 (ABS Inlet Valve Coil LR Circuit Short To Battery) is: Internal wiring short to a powered circuit inside the ABS module housing
Typical repair costs for C1252 range from $300 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A continuously energized inlet valve could block brake fluid pressure to the left rear wheel, causing reduced braking on that corner. This is a critical safety concern requiring immediate repair.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1252 to identify the root cause.
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Quick Info
Category
Chassis
System
Anti-lock Brake System (ABS)
Difficulty
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