Common causes include: Signal shorted to voltage; Failed pressure sensor; Open sensor return or damaged connector.

P0238: Turbocharger/Supercharger Boost Sensor A Circuit High

Q: What does code P0238 mean?

P0238 is the generic OBD-II code for 'Turbocharger/Supercharger Boost Sensor A Circuit High'. The boost sensor A input is above the allowed voltage range. A signal shorted to power can falsely suggest high pressure and cause the computer to limit boost and fueling.

Severity: High Stop or minimize driving and get it looked at right away.

What does P0238 mean?

The boost sensor A input is above the allowed voltage range. A signal shorted to power can falsely suggest high pressure and cause the computer to limit boost and fueling.

Generic OBD-II definition: Turbocharger/Supercharger Boost Sensor A Circuit High. Confirm applicability in your vehicle service information.

Common causes

Signal shorted to voltage
Failed pressure sensor
Open sensor return or damaged connector

Symptoms

Severely reduced acceleration
Limp mode
Check engine light

Diagnostic focus

A high sensor input is different from P0234 overboost. Validate the electrical signal before adjusting a wastegate or replacing boost-control parts.

Can I keep driving with P0238?

Severity: High Stop or minimize driving and get it looked at right away.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

Compare key-on pressure data with ambient pressure
Test the signal and return circuit for high-voltage faults
Check shared reference-supply codes before replacing the sensor

Sources & review

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.