P0235 Turbocharger/supercharger boost sensor A circuit
What P0235 means
The engine computer has a problem with the signal from the boost pressure sensor, which measures pressure in the intake after the turbocharger or supercharger. Without it the computer cannot regulate boost safely and often limits power.
P0235 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 80–400 €
- Workshop time
- 0.3–2 h
- Repair difficulty
- Medium
- DIY possible
- Yes
- Check engine light
- Yes
- Affects emissions test
- Yes
- Limp mode possible
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light on
- Reduced power or limp mode
- Poor acceleration
- Possible black smoke on diesels
Common causes
- Failed boost pressure sensor
- Damaged wiring or corroded connector
- Problem in the 5 V reference circuit
- Sensor clogged with oil from the crankcase breather or turbo
Can I keep driving with P0235?
You can drive, but have it checked within one to two weeks. Expect reduced power if the engine computer switches to limp mode.
What to check first
- Inspect the boost sensor connector and wiring for damage and oil contamination.
- With the key on and engine off, the boost sensor reading should be close to barometric pressure.
- Measure the 5 V reference, ground and signal at the connector.
- Clean or replace the sensor if the wiring is good.
Related codes
- P0234 Turbocharger/supercharger A overboost condition
- P0236 Turbocharger/supercharger boost sensor A range/performance
- P0237 Turbocharger/supercharger boost sensor A circuit low
- P0238 Turbocharger/supercharger boost sensor A circuit high
- P0230 Fuel pump primary circuit
- P0243 Turbocharger/supercharger wastegate actuator A
- P0223 Throttle/pedal position sensor B circuit high
- P0222 Throttle/pedal position sensor B circuit low
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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