Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0558 Brake Booster Pressure Sensor Circuit High

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

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

Symptoms

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

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–250
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

brake booster pressure sensorsensor wiringengine control module

Related codes

P0555P0556P0557P0559P0643

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.