Failed brake booster vacuum sensor; Damaged or disconnected vacuum hose between the booster and the sensor; Wiring harness damage such as open or shorted circuits to the sensor; Corroded or loose electrical connector at the sensor; Faulty brake booster check valve causing incorrect vacuum readings; Internal leak in the brake booster diaphragm affecting vacuum signal

DTC codes / C02xx · Brakes, steering and suspension / C0258

C0258Brake Booster Vacuum Sensor Circuit

Q: What does code C0258 mean?

Brake Booster Vacuum Sensor Circuit. The C0258 code indicates that the brake booster vacuum sensor circuit has a fault, meaning the engine control module or body control module is not receiving a valid signal from the sensor that monitors vacuum assist for the brakes. The computer detects an abnormal voltage or signal range from the sensor, which can affect brake pedal feel and power assist.

The C0258 code indicates that the brake booster vacuum sensor circuit has a fault, meaning the engine control module or body control module is not receiving a valid signal from the sensor that monitors vacuum assist for the brakes. The computer detects an abnormal voltage or signal range from the sensor, which can affect brake pedal feel and power assist.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

Illumination of the brake warning light or ABS (Anti-lock Braking System) light on the dashboard
A hard or stiff brake pedal that requires extra effort to stop the vehicle
A hissing noise from the brake booster area when the engine is running
Reduced engine performance or rough idle due to a vacuum leak
Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

Failed brake booster vacuum sensor
Damaged or disconnected vacuum hose between the booster and the sensor
Wiring harness damage such as open or shorted circuits to the sensor
Corroded or loose electrical connector at the sensor
Faulty brake booster check valve causing incorrect vacuum readings
Internal leak in the brake booster diaphragm affecting vacuum signal

How to diagnose and fix it

Inspect the vacuum hose and sensor connector for obvious damage, cracks, or disconnection
Use a scan tool to read live data from the vacuum sensor and compare to expected values
Perform a voltage and resistance test on the sensor circuit according to the manufacturer's specifications
Check the brake booster check valve and vacuum supply with a vacuum gauge
Replace the brake booster vacuum sensor if testing confirms it is faulty
Repair any damaged wiring or connectors in the sensor circuit
Clear the code and verify the repair with a test drive and re-scan

Common Misdiagnosis of Brake Booster Sensor

A vacuum leak from a cracked hose or faulty check valve often sets this code, so always inspect the entire vacuum path before replacing the sensor.
The sensor may be misdiagnosed when the actual problem is a failing brake booster, which can cause similar symptoms and voltage irregularities.
Intermittent codes can be caused by a loose connector or chafed wiring that only acts up under certain engine vibrations or temperature changes.
Some vehicles use the vacuum sensor for other engine functions, so a fault can also cause drivability issues that seem unrelated to the brakes.
Always verify the sensor's reference voltage and ground circuits; a bad ground can mimic a failed sensor.

Can I keep driving with C0258?

If the brake pedal feels normal, you can drive cautiously to a repair shop, but avoid heavy braking or towing. If the pedal is hard or braking performance is reduced, stop driving and have the vehicle towed to prevent an accident.

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.