Turbocharger/Supercharger "A" Overboost Condition
Boost pressure exceeded the upper limit during commanded full load. The ECU usually drops fuel and ignition or commands the wastegate fully open to protect the engine; persistent overboost can crack pistons or rings.
Affected components
- Turbocharger
- Wastegate actuator
- Boost pressure sensor
- Vacuum lines
Common causes
- High likelihood: Wastegate stuck closed (carbon, broken linkage)
- Medium likelihood: Boost control solenoid failed
- Medium likelihood: Vacuum/pressure line cracked
Possible symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
- Reduced-power or limp mode may occur
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.