C05CD: Brake Master Cylinder Piston Position Sensor B Circuit Voltage High

Brake master cylinder piston position sensor B signal voltage above expected range.

High severity. Can I keep driving?The regular brakes usually keep working, but without ABS or the driver aids. Drive very carefully and go to a repair shop; if the pedal feel changes, do not keep driving.

Symptoms

ABS warning light on
ESC/stability control deactivated
Possible reduced brake assist
Speedometer may behave erratically

Most likely causes

Signal wire shorted to battery

What to check, in order

Start with the simplest. You can tick off each step.

Check that the brakes respond normally and check the fluid level
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Read the ABS codes with a multi-system scanner
Check the wheel sensors, connectors, and wiring
Compare the speeds of all four wheels in live data
Leave any work on the hydraulic circuit to a professional

Good to know

Repair difficulty: hard
It can trigger limp mode.

What each character of C05CD means

C: Chassis
0: Generic code: same on every make
5: Subsystem depends on the code range
CD: Specific fault in that system

Frequently asked questions

Can I keep driving with code C05CD?

The regular brakes usually keep working, but without ABS or the driver aids. Drive very carefully and go to a repair shop; if the pedal feel changes, do not keep driving.

What causes code C05CD?

The most common causes are: signal wire shorted to battery.

Related codes

C05CABrake Master Cylinder Piston Position Sensor A Circuit Voltage High

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.