Code result
P0039
Turbocharger/Supercharger Bypass Valve A Control Circuit Range/Performance
High severity
What it means
The wastegate or bypass valve A on the turbo/supercharger does not respond mechanically as expected to its control signal. Boost pressure deviates from target.
Is it safe to drive?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
Wastegate sticking from carbon
highOne of the most commonly reported causes for this code — check this first.
Vacuum/boost line leaking
mediumA plausible cause — test and verify before replacing parts.
Wastegate actuator worn
mediumA plausible cause — test and verify before replacing parts.
Related help
Get the full diagnosis
Add your vehicle and see step-by-step repair help, recalls, and TSBs in Wrenchify.
Diagnose P0039 freeNo credit card required