C1241 indicates the ABS control module has detected a short-to-ground in the circuit for the hydraulic pressure differential switch. This switch monitors pressure imbalance between brake hydraulic circuits and is typically integrated into or mounted on the ABS actuator/master cylinder assembly. The fault causes the ABS module to set the code and usually disables ABS and stability-control functions while leaving normal base braking operational.
The switch itself can develop an internal short to ground, especially if it is integral to the ABS actuator assembly. This is the most common root cause of C1241.
The signal wire between the switch and the ABS module may be chafed, pinched, or damaged, creating an unwanted path to ground.
Moisture, brake fluid, or corrosion in the switch or ABS module connector can bridge terminals and cause a short-to-ground condition.
If the pressure switch is not serviced separately, an internal fault within the actuator assembly can produce the same short-circuit reading.
A rare internal failure of the ABS control module input circuit can set this code; it should only be considered after the switch, wiring, and connectors have been ruled out.
No. This code is most often caused by a faulty pressure differential switch, damaged wiring, or a connector issue. Replacing the ABS control module is usually unnecessary and should only be done after the switch circuit and wiring are proven good.
Base braking typically remains normal, but ABS and stability/traction control may be disabled. You can drive cautiously to a repair facility, but avoid emergency or slippery-road conditions where those systems would be needed.
It depends on the vehicle design. Some systems allow the pressure differential switch to be replaced separately, while others require replacement of the ABS actuator or master cylinder assembly because the switch is integrated.
Once the short-to-ground is repaired, the code must be cleared with a scan tool. The lights should stay off if the root cause was fixed; if they return, further diagnosis of the switch or actuator is needed.