What it means
Wastegate actuator B control voltage above expected range. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The wastegate actuator B moves the turbocharger or supercharger wastegate to regulate boost. The control module monitors actuator B's electrical control and compares commanded boost with manifold pressure. P0250 sets when actuator B's control voltage is higher than the expected range, which can leave boost control unable to follow the request.
Common causes
Most likely first.
- Damaged wiring or connector
- Wastegate actuator B failure
- Poor electrical connection
- Control module fault
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
How to diagnose it
- Record freeze-frame data and compare commanded with actual boost to see when the fault and power loss occur.
- Inspect actuator B's connector and wiring for corrosion, loose pins, heat damage, chafing, or a short to power.
- Check that the wastegate linkage and any connected vacuum or pressure hoses are intact and move freely.
- Use a scan tool to command actuator B, if supported, and observe whether its position and boost response follow the request.
- Test actuator B's control circuit and actuator against the manufacturer's specification before considering a control-module fault.
Common fixes
- Repair damaged wiring or secure and clean actuator B's connector.
- Replace a split or disconnected boost-control hose.
- Repair a sticking wastegate linkage or replace a failed actuator B.
- Repair or replace the control module only after its circuit and outputs have been verified.
Can I keep driving?
Avoid hard acceleration, towing, and sustained high speeds because boost may be uncontrolled or reduced and the engine may enter a reduced-power mode. Stop if power loss is severe or smoke is heavy; continued operation can worsen engine or turbocharger damage.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.