P012BTurbocharger/Supercharger Inlet Pressure Sensor A Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- The turbocharger/supercharger inlet pressure sensor A sits between the air filter and the compressor. The engine uses it for the compressor pressure ratio, to judge air filter restriction (ambient minus inlet pressure) and to cross-check the other pressure sensors. P012B is a plausibility fault: the signal is electrically valid but stuck or offset. On GM's supercharged 6.2 V8 the sensor must read 50–115 kPa and agree within 10 kPa with MAP and ambient pressure after the engine has been off for more than 8 s; while running, it is compared with modelled values (fault above about 25–30 kPa). GM normally needs two trips, one in some 2019 applications. In operation inlet pressure is slightly below ambient because of filter losses, so a clogged filter or blocked intake lowers it further.
- What you may notice
- Check engine light on
- Loss of power or boost limitation
- Possibly no noticeable symptoms
- Likely causes
- LikelySensor oiled (crankcase vent often joins before the compressor) or drifted
- PossibleAir filter heavily clogged or intake blocked or collapsed
- PossibleLeak in the intake pipe between filter and compressor or at the sensor flange
- PossibleHigh resistance in the wiring
- RareComparison sensor (MAP, baro, MAF) wrong or software
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.