Boost sensor reading too high.
P0238 — also written PO238, P 0238, 0238 — is the OBD-II code for turbocharger boost sensor 'a' high input. Same code, same fix: this page covers every spelling of it.
Turbocharger boost sensor high — usually a faulty boost pressure sensor on the intake, or rarely an overboost condition from a sticky wastegate.
P0238 is a sensors fault code, typically costing £80–£350 to put right in a UK garage.
What P0238 actually feels like to drive
- Limp mode under heavy acceleration
- Engine power restored after key cycle
- No obvious sounds or smoke — fault is purely electronic
- Code clears, then returns within 50–100 miles
- Sometimes triggers a stored P0299 alongside
What causes P0238?
- Sensor fault
- Wiring short
UK vehicles that throw P0238 most often
- BMW 320d / 520d / X3 / X5 diesel
- Mercedes C/E-Class OM651 diesel
- VW / Audi 2.0 TDI
- Ford Mondeo / S-Max 2.0 TDCi
- Mini Cooper D
How P0238 is fixed
- Sensor replacement
The P0238 misdiagnosis that wastes money
This code points to the sensor first, but on BMW N47 we always check the wiring loom near the EGR cooler — chafing causes false high readings. Replacing the sensor will give you a few weeks of relief before the chafed wire shorts again.
What a UK garage should charge for P0238
Boost pressure sensor £45–£120 fitted, loom repair £80–£180, wastegate actuator £180–£420, scan-tool boost data analysis £45–£70.
P0238 repair cost in the UK
Most P0238 repairs land between £80–£350 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0238
If your scan tool shows boost pressure readings of 3 bar+ when commanded 1.5 bar, that's a true overboost — not just a sensor fault. Get the wastegate operation checked before clearing and driving.
Can you drive with P0238?
Drivable.
Urgency: medium.