P23AA code meaning
Turbocharger/Supercharger Bypass Valve A Stuck
Powertrain system Generic code P23xx codes Check engine light
What P23AA means
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.
P23AA at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P23AA
- Reduced boost and power
- Fluttering or surging noise when lifting off
- MIL on, possibly limited power mode
Common causes of P23AA
- Most likelyValve or actuator mechanically seized (deposits, wear)
- PossibleFaulty electric actuator or position sensor of the valve
- PossibleDamaged linkage or valve plate
- Less likelyHigh resistance in wiring or connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Turbocharger bypass valveTurbocharger bypass valve wiring
What each part of P23AA means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| AA | The exact fault in that area. |
What to do next
- Note P23AA and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P23AA
What does P23AA mean?
P23AA means "Turbocharger/Supercharger Bypass Valve A Stuck". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P23AA?
Drive gently and only to a workshop. With P23AA the car can go into limp mode (reduced power) to protect itself.
Will P23AA fail an emissions test?
Yes, it can. P23AA is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P23AA to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P23AA clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.