Powertrain, generic (extended)

P23AA Turbocharger/Supercharger Bypass Valve A Stuck

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P23AA concerns bypass valve A of a turbocharger or supercharger, which opens a path around the compressor to relieve boost when the throttle closes or at part load. The code means the valve no longer follows its command and sits fixed. GM applies P23AA to the electronically positioned supercharger bypass valve of the 2019 Corvette LT5: if the measured position deviates from the target by more than 25 % for at least 1 s while the valve is barely moving (under ±10 % per second), 10 failures in 14 samples at 6.25 ms set a Type A fault with the MIL in the first trip. The circuit codes P0033 to P0035 and the mechanical test P2261 cover other faults of the valve. Stuck open it costs boost and power; stuck closed it can cause compressor surge and noise on lift-off.

Likely causes

Valve or actuator mechanically seized (deposits, wear)
Faulty electric actuator or position sensor of the valve
Damaged linkage or valve plate
High resistance in wiring or connector

Symptoms

  • Reduced boost and power
  • Fluttering or surging noise when lifting off
  • MIL on, possibly limited power mode

Repair estimate

DifficultyHardWorkshop job
Parts and labour€150–1,200
Time1–4 h

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

Parts involved

turbocharger bypass valveturbocharger bypass valve wiring

Related codes

P0033P0034P0035P2261P0299P0234

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