P012B code meaning
Turbocharger/Supercharger Inlet Pressure Sensor A Circuit Range/Performance
Powertrain system Generic code P01xx codes Check engine light
What P012B means
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.
P012B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P012B
- Check engine light on
- Loss of power or boost limitation
- Possibly no noticeable symptoms
Common causes of P012B
- Most 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
- Less likelyComparison sensor (MAP, baro, MAF) wrong or software
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Turbocharger inlet pressure sensor aAir filterIntake ductSensor wiring
What each part of P012B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 2B | The exact fault in that area. |
What to do next
- Note P012B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P012B
What does P012B mean?
P012B means "Turbocharger/Supercharger Inlet Pressure Sensor A Circuit Range/Performance". The turbocharger/supercharger inlet pressure sensor A sits between the air filter and the compressor. It is a generic code, so it means the same on every make.
Is it safe to drive with P012B?
Drive gently and only to a workshop. With P012B the car can go into limp mode (reduced power) to protect itself.
Will P012B fail an emissions test?
Yes, it can. P012B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P012B to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P012B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.