P0242
Turbocharger/Supercharger Boost Sensor B Circuit High
Turbo / boost control
Generic OBD-II
High
What it means
P0242 means boost-pressure sensor B is reading a voltage above its normal range — typically an open signal wire or a short to power. With an untrustworthy boost signal, the ECM usually limits boost and power to protect the engine, so the car feels down on power rather than failing to run.
High
Can I keep driving? Usually driveable with reduced power; avoid extended high-load driving until the boost-sensor circuit is repaired.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced engine power or limited boost
- Hesitation or surging on acceleration
- Rough idle in some cases
Common causes
Most likely first
- Open circuit or short to power in the boost-sensor signal wiringLikely
- Failed boost-pressure sensorCommon
- Loose or corroded sensor connectorCommon
- Rarely, a failed ECMLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame and inspect the sensor connector and wiring for an open or a short to power.
- Check the sensor ground and reference, then compare the signal voltage to spec.
- Replace the boost-pressure sensor if wiring and grounds are good but the signal stays high.
- Repair damaged wiring, clear the code, and road-test.
FAQ
Quick answers
Is it safe to drive with P0242?+
Usually yes, but expect reduced power while the ECM limits boost. Have it fixed before extended or high-load driving.
Can I just clear P0242?+
It will return until the open or short in the sensor circuit is repaired.
Related codes
Often seen with P0242
Read & clear P0242 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