Powertrain, generic (extended)

P2C2D Turbocharger/Supercharger Bypass Valve B Position Exceeded Learning Limit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

Electrically positioned compressor bypass valves have their end stops relearned regularly so that the sensor reading can be converted into a true opening. P2C2D means that for valve B, belonging to the second charger, a learned stop came out beyond the allowed window. No manufacturer documents the B-side code. GM shows the routine for valve A on the 2019 Corvette ZR1: once the engine is switched off, the module first drives the valve closed and stores the reading, which must lie between 85 and 95 %, then the open stop, expected between 10 and 20 %; a value outside sets P2BBE immediately as Type A, provided no sensor or circuit fault is active. Deposits, a bent flap, gear wear or a shifted sensor are typical causes. A repair is only confirmed after the next key-off learn.

Likely causes

Carbon or oil deposits preventing the valve from reaching its stop
Worn actuator gear or loose sensor magnet
Valve replaced without relearn or with incorrect part

Symptoms

  • Check engine light after a key-off
  • Boost control less precise, possible surge noise

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,200
Time1–4 h

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

Parts involved

turbo bypass valve bwiring harnessecm

Related codes

P2BBEP2C29P2C2AP2C2BP2C2C

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