What Does C1241 Mean?
The ABS control module has detected a short circuit to ground on the hydraulic pressure differential switch input circuit. The signal wire is being pulled to ground potential (0V) when it should not be, indicating a wiring fault, failed switch, or grounding issue that prevents the module from reading the true state of the pressure differential switch.
Safety Warning
Brake hydraulic integrity monitoring is disabled. A dangerous brake fluid leak could develop without warning. Diagnose and repair before driving.
Common Causes
35%
Chafed or pinched wiring shorting the signal wire to a ground point or vehicle body metal
25%
Internally shorted pressure differential switch with contacts fused to ground
20%
Water intrusion into the switch connector creating a conductive ground path through corrosion
15%
Damaged ABS module connector with a ground pin contacting the signal pin
5%
ABS module internal driver circuit failure pulling input to ground
Diagnostic Steps
1
Step 1: Disconnect the pressure differential switch connector. Measure resistance from each signal wire to ground at the harness side. Should read OL (infinite). If near 0 ohms, wire is shorted to ground.
2
Step 2: If the harness tests clean, measure resistance across the switch terminals to ground. A near-zero reading indicates an internally shorted switch.
3
Step 3: Trace the wiring harness from the switch to the ABS module, looking for pinch points at body panels, brackets, or where the harness passes through grommets.
4
Step 4: Inspect the ABS module connector for moisture, corrosion, or bent pins that could create an unintended ground path.
5
Step 5: Repair the short to ground, apply dielectric grease to connectors, clear codes, and verify correct switch behavior in live data.
Estimated Repair Cost
$60 - $300
Parts + labor, varies by vehicle and location
The ABS control module has detected a short circuit to ground on the hydraulic pressure differential switch input circuit. The signal wire is being pulled to ground potential (0V) when it should not be, indicating a wiring fault, failed switch, or grounding issue that prevents the module from readin...
The most common cause of C1241 (ABS Hydraulic Pressure Differential Switch Input Short Circuit To Ground) is: Chafed or pinched wiring shorting the signal wire to a ground point or vehicle body metal
Typical repair costs for C1241 range from $60 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Brake hydraulic integrity monitoring is disabled. A dangerous brake fluid leak could develop without warning. Diagnose and repair before driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1241 to identify the root cause.
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Quick Info
Category
Chassis
System
Anti-lock Brake System (ABS) / Hydraulic Brake System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
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