Home›Trouble Codes›C0571

C0571 — Brake Pressure Sensor C Circuit Low

Generic OBD-II · all makesChassis

C0571 indicates that the brake pressure sensor 'C' circuit is reporting a voltage lower than the expected range. This typically points to a short-to-ground, open circuit, or a failed sensor, and is most often found in vehicles with electronic brake control modules (EBCM) or ABS systems.

Symptoms

What causes it — most likely first

1. Faulty brake pressure sensor C

The sensor itself has failed internally, causing a low output signal. This is the most common root cause for a circuit-low code.

2. Short to ground in sensor circuit

A damaged wire or connector pin that contacts ground can pull the signal voltage low, triggering the code.

3. Open circuit in sensor wiring or connector

A broken wire or poor terminal connection can cause an open circuit, which the module interprets as a low-voltage condition.

4. Corroded or damaged sensor connector

Moisture, corrosion, or bent pins at the sensor connector can create high resistance or intermittent low voltage.

5. Low system voltage or weak battery

A severely discharged battery or charging system fault can cause all sensor circuits to read low, but this is less common as a single-circuit code.

6. Faulty ABS/brake control module (EBCM)

Internal module failure is rare but possible if the module's input circuitry is damaged. This should only be considered after thoroughly testing the sensor and wiring.

How it's diagnosed

  1. Verify battery voltage and charging system are within specification (12.6V+ engine off, 13.5-14.5V running).
  2. Inspect the brake pressure sensor C connector and wiring for damage, corrosion, or loose pins.
  3. Measure sensor signal voltage at the module connector with the ignition on (engine off) – should typically be around 0.5V at zero pressure.
  4. Check sensor ground and reference voltage (usually 5V) at the connector.
  5. If voltage is low, disconnect the sensor and measure the signal wire at the module side – if voltage returns to normal, the sensor is likely shorted internally.
  6. Perform a resistance check of the sensor between signal and ground; compare to manufacturer specifications.
  7. If all wiring and sensor tests pass, consider a module fault or need for reprogramming.

Code facts & related codes

SystemChassis
StandardizationSAE generic — identical on every make
Related codesC0569 — Brake Booster Solenoid Circuit PerformC0570 — Brake Booster Travel Sensor Circuit HiC0572 — Brake Pressure Sensor C Circuit HighC0573 — Brake Pressure Sensor C CircuitopenC0574 — Brake Pressure Sensor C Circuit RangepC0575 — Brake Pressure Sensor D Circuit Low

Frequently asked

Can I drive the car with a C0571 code?

Yes, in most cases the vehicle remains drivable, but ABS and stability control functions will be disabled. Braking with the base hydraulic system still works. However, driving without ABS in slippery conditions increases stopping distance and risk of wheel lockup.

Do I need to replace the ABS module for code C0571?

Rarely. The most common fix is replacing the brake pressure sensor itself or repairing a wiring issue. The module is often blamed but is actually the least likely cause. Always test the sensor and circuit first.

What is 'brake pressure sensor C'?

Many vehicles have multiple brake pressure sensors (e.g., A, B, C) to monitor pressure in different hydraulic circuits. Sensor C is typically associated with a specific channel of the ABS modulator or a secondary circuit. The exact location varies by vehicle.

Can a low battery cause this code?

It is possible but uncommon for a low battery to trigger a single sensor circuit code. More often, low battery voltage causes multiple system faults. If the code returns after charging the battery and clearing the code, the sensor or wiring is the likely culprit.