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.

Real-world scan data

Seen in

1,553

scans in the past year

Found in

0.2%

of scans

0.4%

of scans that found faults

Appears alongside · share of P0238 scans

P0113in 30.2% of scans

P0098in 26.6% of scans

P0101in 18.0% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

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.

Read & clear P0238 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX