Powertrain, generic (extended)

P2C2B Turbocharger/Supercharger Bypass Valve B Position Sensor Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

With P2C2B the position signal of compressor bypass valve B lies below the lowest value a healthy sensor delivers. Likely reasons are a signal wire grounded against the engine, an open 5 V reference or a sensor that has failed low. For valve B no public manufacturer data exist. For valve A, GM's 2019 Corvette ZR1 (supercharged LT5) shows how such a test is built: a raw reading under 10 % of the reference in 10 of 14 samples taken 100 ms apart, only with relay voltage of at least 11 V and the engine not cranking, gives a Type A fault with immediate MIL (P2BBC). The open-circuit case is P2C2A, the high case P2C2C. Since valve position can no longer be confirmed, boost is typically reduced.

Likely causes

Signal wire of the position sensor shorted to ground
Missing 5 V reference at the sensor
Position sensor in the valve actuator failed low

Symptoms

  • Check engine light
  • Reduced boost pressure

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 bwiring harnessecm

Related codes

P2C2AP2C2CP2BBCP2C29

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