Powertrain, generic · Fuel and air metering, auxiliary emission controls

P0033 Turbocharger/Supercharger Bypass Valve A Control Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The turbocharger bypass valve A is the compressor recirculation (diverter) valve: it connects the pressure side of the compressor with the intake side upstream of the turbocharger. It opens when the throttle closes quickly at high boost, so the compressor does not surge and the compressor wheel keeps its speed for the next acceleration. It is not the wastegate, which bypasses exhaust gas around the turbine and has its own codes. The valve is either electric or a vacuum unit controlled by a solenoid. P0033 is the general circuit fault, usually an open circuit: the voltage at the control output does not match the command.

Likely causes

Wire or connector interrupted, corroded or chafed
Solenoid coil or electric bypass valve faulty
Supply missing, e.g. fuse or main relay
Output driver in the engine control module faulty

Symptoms

  • Check engine light on
  • Fluttering or hissing when lifting off the throttle if the valve stays closed
  • Weak response after gear changes
  • Too little boost if the valve stays open

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–350
Time0.5–2 h

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

Parts involved

turbocharger bypass valveturbocharger bypass valve wiringengine control module

Related codes

P0034P0035P0039P2261P00C0P0299

References: law.cornell.edu, gsi.ext.gm.com, saabwisonline.com, ms-motorservice.com.