P23AA
Turbocharger Bypass Valve A Stuck
The turbocharger bypass valve A (compressor bypass for surge protection or wastegate-style boost relief) is mechanically stuck. Boost control is impaired - either no relief on overspeed or no boost build-up depending on which position the valve is stuck in.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Common causes
Ordered by how often each turns out to be the cause.
- Valve stuck due to debris or actuator failureCommon
Parts involved
- Turbo Bypass Valve A
P23AA is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.