P0238
Turbocharger/Supercharger Boost Sensor A Circuit High
Turbo/supercharger boost control
Generic OBD-II
High
What it means
P0238 means the boost-pressure sensor circuit is reading higher than its valid range — an electrical high signal rather than genuine overboost. The ECM relies on this sensor to manage boost, so when it can't trust the reading it typically limits boost and drops into reduced-power mode. The car still drives, but expect it to feel flat until the sensor or wiring is fixed.
High
Can I keep driving? Usually drivable but often in reduced-power limp mode — the ECM cuts boost when it can't trust the sensor. Expect sluggish performance until fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power / limp mode (boost limited)
- Hesitation or flat spots under acceleration
- Poor fuel economy
Common causes
Most likely first
- Failed boost-pressure sensor reading highLikely
- Signal wire shorted to voltage or to another circuitCommon
- Corroded or loose sensor connectorCommon
- Sensor reference/ground fault raising the signalLess often
- Failed engine control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check the boost sensor's live reading against actual manifold/boost pressure.
- Inspect the sensor connector and wiring for a short to voltage, damage, or corrosion.
- Verify the sensor's ground and reference voltage are correct.
- If the signal stays high with good wiring, replace the boost-pressure sensor.
- Clear the code and road-test under boost to confirm normal readings.
FAQ
Quick answers
Is it safe to drive with P0238?+
Short-term, yes, but the car will likely be down on power in limp mode. Avoid hard acceleration and get the sensor or wiring diagnosed.
Can I just clear P0238?+
It returns as soon as the ECM reads the high signal again unless the sensor or its wiring is repaired.
Related codes
Often seen with P0238
Read & clear P0238 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX