P0238 indicates that the boost pressure sensor in a turbocharged or supercharged engine is reporting a higher voltage than expected, meaning the ECM detects excessive boost pressure. The code is triggered when the sensor's signal exceeds the calibrated maximum.
The sensor may be internally shorted or its signal circuit can develop a fault that sends an excessively high voltage to the ECM.
Corroded, damaged, or loose wiring/connector can cause a high voltage condition in the sensor circuit.
A malfunctioning wastegate or boost control valve can allow excess boost pressure to develop, raising sensor readings.
An unintended air leak can cause the engine to produce higher than expected boost, leading to a false high reading.
A PCM failure that misinterprets sensor data is possible but uncommon; it is typically considered only after other components are verified.
Usually not; the PCM rarely causes this code, and most often the issue is a faulty sensor, wiring, or boost control component.
Driving is possible but may result in reduced power and fuel efficiency; the issue should be addressed promptly.
In turbocharged or supercharged engines the boost pressure sensor often functions like a MAP sensor, measuring intake pressure.