A short to ground or an open circuit in the wiring harness or connector for brake pressure sensor F.; A failed brake pressure sensor F itself, due to internal electrical failure or contamination.; Corroded, loose, or water-intruded electrical connectors at the sensor or ABS module.; Low brake fluid level or air trapped in the hydraulic system, causing the sensor to read outside its expected range.; A faulty ABS control module that misinterprets a valid sensor signal.; A damaged or pinched wire caused by previous repairs, road debris, or vibration.; A poor ground connection shared by the sensor circuit, leading to a low reference voltage.

DTC codes / C05xx · Brakes, steering and suspension / C05C6

C05C6Brake Pressure Sensor F Circuit Low

Q: What does code C05C6 mean?

Brake Pressure Sensor F Circuit Low. C05C6 means the antilock braking system (ABS) module has detected an abnormally low voltage signal on the circuit for brake pressure sensor F, which is one of several pressure sensors used to monitor hydraulic brake pressure. The computer compares this signal against expected values and flags the code when the voltage stays below the acceptable threshold for a set period, indicating a short to ground, an open circuit, or a faulty sensor.

C05C6 means the antilock braking system (ABS) module has detected an abnormally low voltage signal on the circuit for brake pressure sensor F, which is one of several pressure sensors used to monitor hydraulic brake pressure. The computer compares this signal against expected values and flags the code when the voltage stays below the acceptable threshold for a set period, indicating a short to ground, an open circuit, or a faulty sensor.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

The ABS warning light and often the red brake warning light illuminate on the dashboard.
The traction control and stability control (ESC) warning lights may also turn on because these systems share the brake pressure signal.
The ABS may be disabled, so the wheels can lock during hard braking and the pedal may feel different.
A soft or spongy brake pedal if the low signal is caused by air in the hydraulic system or a failing sensor.
Often no symptoms besides the warning light, especially if the fault is intermittent or only affects a secondary pressure sensor.
In some vehicles, the cruise control or hill-start assist may stop working because they rely on brake pressure data.

Common causes, most likely first

A short to ground or an open circuit in the wiring harness or connector for brake pressure sensor F.
A failed brake pressure sensor F itself, due to internal electrical failure or contamination.
Corroded, loose, or water-intruded electrical connectors at the sensor or ABS module.
Low brake fluid level or air trapped in the hydraulic system, causing the sensor to read outside its expected range.
A faulty ABS control module that misinterprets a valid sensor signal.
A damaged or pinched wire caused by previous repairs, road debris, or vibration.
A poor ground connection shared by the sensor circuit, leading to a low reference voltage.

How to diagnose and fix it

Check the brake fluid level and inspect for leaks; top up or bleed the system if needed.
Visually inspect the sensor, its connector, and the wiring harness for damage, corrosion, or loose pins.
Use a scan tool to read live data from brake pressure sensor F and compare it with a mechanical pressure gauge.
Perform a voltage drop test on the sensor's ground and signal circuits to locate excessive resistance.
Disconnect the sensor and measure resistance and voltage according to the manufacturer's specifications.
If the sensor is faulty, replace it and clear the code; then verify the live data reads correctly.
If the wiring and sensor are good, test the ABS module and its connectors for internal faults or software issues.

Why brake pressure sensor F codes mislead

A low signal code is often caused by a simple chafed wire or corroded connector, not by a failed sensor, so always inspect the harness before replacing parts.
Brake pressure sensor F is sometimes a secondary sensor used for stability control, so the base brakes may still work normally even though the ABS and ESC lights are on.
Low brake fluid or air in the system can trigger this code because the sensor reads pressure outside its expected range, so hydraulic checks come before electrical ones.
After replacing the sensor or repairing wiring, some vehicles require a recalibration or a relearn procedure with a scan tool to clear the code permanently.
A weak battery or charging system can cause intermittent low-voltage signals on sensor circuits, so check the charging system if the code returns.

Can I keep driving with C05C6?

You can usually drive the car to a repair shop, but avoid hard braking and slippery conditions because the ABS may be disabled. If the red brake warning light is also on or the pedal feels soft, stop driving and have the vehicle towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.