When the code is set
The ECM uses the boost pressure sensor to monitor the pressure in the intake. If it stays above the maximum permitted value for a few seconds, the ECM stores P0234 and normally cuts engine power.
Can I keep driving?
Have it checked soon
Go easy on the engine: no hard acceleration, no towing a trailer and no full throttle up hills, because excess boost can seriously damage the engine. Drive gently and only as far as a garage. If the engine knocks or loses power, stop and have the car recovered.
Symptoms
- The check engine light is on.
- Limp mode with reduced power.
- Power cutting out under hard acceleration.
- Knocking (pinging) under load.
Common causes
- A sticking wastegate or wastegate actuator.
- A faulty boost control solenoid valve or its vacuum hose.
- Sticking variable turbo vanes (on diesel engines).
- A faulty boost pressure sensor or its wiring.
- A faulty turbocharger or ECM (less common).
How to find the cause
A mechanic usually works like this:
- Read all codes and freeze frame data.
- Inspect the wiring and vacuum hoses of the boost control system.
- Compare actual and requested boost pressure on a test drive; if the difference is small, suspect the sensor.
- Test the wastegate or vanes and the boost control solenoid valve.
Other ways the code is written
Scan tools and workshop printouts sometimes show the code with extra characters:
- P023400
Related codes
Frequently asked questions
Evoca fault code diagnostics is an informational aid and does not replace a professional inspection of your vehicle. Only an inspection of the vehicle at a workshop can confirm the cause of a fault.
Check P0234 for your car
Enter the code and, if you like, your car details. You get a free report with possible causes and next steps by email.