Powertrain, generic (extended)

P2BBC Turbocharger/Supercharger Bypass Valve A Position Sensor Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2BBC sets when the position signal of the bypass valve A sensor sits too low – usually an open signal wire, a short to ground or a lost 5 V supply to the sensor. GM uses the code on the 2019 Corvette ZR1 with the supercharged LT5, whose electronic compressor recirculation valve (eCRV) reports its position as a share of the reference voltage: a raw value under 10 % in 10 of 14 samples taken every 100 ms counts as a failure, checked while relay voltage is at least 11 V and the engine is not cranking. It is a Type A fault, so the MIL comes on in the first trip. The opposite case, a signal stuck near the reference, is P2BBD; a valve that does not follow its command is P23AA. Unable to trust the valve position, the module typically limits boost.

Likely causes

Signal wire shorted to ground or chafed against the engine
Open 5 V reference wire or reference shorted by another sensor on the same supply
Pushed-out or corroded terminal in the valve connector
Defective position sensor in the valve actuator

Symptoms

  • Check engine light on in the first trip
  • Limited boost and weaker acceleration
  • Possibly further 5 V reference codes if the supply is shorted

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–900
Time0.5–3 h

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

Parts involved

turbo bypass valve awiring harnessecm

Related codes

P2BBBP2BBDP2BBEP23AAP2C2B

References: law.cornell.edu, gsi.ext.gm.com, patents.google.com.