P0558: Brake Booster Pressure Sensor Circuit High

The brake booster pressure sensor (5 V reference, signal, ground) measures the vacuum in the brake booster. On direct-injection, turbo, stop-start and hybrid engines intake vacuum is scarce, so the engine module watches it and creates vacuum when needed – closing the throttle, suppressing engine stop or running an electric vacuum pump. That makes it an input to idle and throttle control. P0558 means the signal voltage is too high: GM 2018 above 95 % of the reference in 2000 of 2400 samples (about 30 s), GM 2006 above 4.89 V; type B, two trips. Typical are a signal shorted to 5 V or battery voltage or an open sensor ground. A real loss of vacuum does not set P0558 but P0556 or, depending on the maker, P050F.

Medium severity. Can I keep driving?Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.

Symptoms

Check engine light or brake booster warning
Stop-start inactive
Often no change in driving

Most likely causes

Sensor ground open (connector, wire)
Signal shorted to 5 V reference or battery voltage
Sensor faulty
Engine module

What to check, in order

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

Check the hoses, clamps, and intercooler
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Compare commanded and actual pressure in live data
Check the actuator's movement
Check the vacuum hoses and the solenoid valve
Check the oil and the turbo shaft play before replacing it

Good to know

Repair difficulty: medium

What each character of P0558 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
5: Speed and idle
58: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0558?

Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.

What causes code P0558?

The most common causes are: sensor ground open (connector, wire); signal shorted to 5 V reference or battery voltage; sensor faulty.

Related codes

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.