P012B
Turbocharger/Supercharger Inlet Pressure Sensor A Circuit Range/Performance
Turbo / boost control
Generic OBD-II
High
What it means
P012B means the turbo or supercharger inlet pressure sensor "A" is reading a value that doesn't match expected conditions — it's out of range or implausible. Because the ECM uses this signal to manage boost, it may limit power or enter a reduced-power mode until the sensor, its wiring, or a boost leak is sorted out.
High
Can I keep driving? You can drive gently, but boost may be limited and the engine can drop into reduced-power mode; fix it before hard acceleration or towing.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or boost / limp mode
- Hesitation or poor acceleration under load
Common causes
Most likely first
- Faulty turbocharger/supercharger inlet pressure sensorLikely
- Open, shorted, or corroded wiring or connector at the sensorCommon
- Boost or vacuum leak giving the sensor an implausible readingCommon
- Intercooler or intake restriction affecting inlet pressureLess often
- Faulty ECM/PCM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and compare the inlet-pressure reading to actual/barometric pressure on a scan tool.
- Inspect the sensor connector and wiring for damage or corrosion.
- Check the intake and boost plumbing for leaks or restriction.
- Replace the sensor if it reads out of range with good wiring; repair leaks.
- Clear and retest under load.
FAQ
Quick answers
Is it safe to drive with P012B?+
Light driving is usually fine, but the ECM may cap boost or cut power to stay safe. Avoid hard acceleration or towing until it's repaired.
Can I just clear P012B?+
It returns once the ECM sees the implausible pressure signal again. The sensor, its wiring, or a boost leak has to be addressed first.
Related codes
Often seen with P012B
Read & clear P012B 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