How severe is fault code C1241?

Serious — Stop or limit driving

OBD Code C1241: ABS Hydraulic Pressure Differential Switch Input Short Circuit To Ground

Q: What are the symptoms of fault code C1241?

ABS warning light illuminated on dashboard, Loss of ABS functionality during braking, Brake pedal feels spongy or requires harder pressure

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What This Actually Means

In plain language — no jargon

The ABS system's pressure sensor has a short circuit to ground, like a wire touching bare metal and creating an unwanted path for electricity. The ABS control module can't read the hydraulic pressure accurately, preventing proper brake function.

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Symptoms You May Notice

3 known symptoms for this code

ABS warning light illuminated on dashboard

Loss of ABS functionality during braking

Brake pedal feels spongy or requires harder pressure

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Embedded Systems Insight

What the ECU/ECM is actually computing

The ECU monitors the voltage signal from the hydraulic pressure differential switch, which should toggle between high and low states as pressure changes. A short to ground pulls this voltage to 0V continuously, indicating a wiring or connector fault rather than actual pressure loss.

Voltage & Parameter Thresholds

Parameter	Normal Range	Fault Condition
Pressure Switch Voltage	4.5-5.0V or 0.2-0.5V (toggling)	Stuck at 0V (shorted to ground)
Signal Resistance	1k-10k ohms	Less than 100 ohms or 0 ohms

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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex

1

Wiring harness connector

Inspect and reseat the ABS pressure sensor connector at the hydraulic module for corrosion or loose pins.

2

Wiring and insulation

Check the sensor wiring between the pump module and ECU for pinched, abraded, or damaged insulation causing a ground short.

3

Hydraulic pressure differential switch

Replace the switch assembly if wiring is intact and connector is clean, as internal short is likely.