Powertrain, generic · Fuel and air metering

P012C Turbocharger/Supercharger Inlet Pressure Sensor A Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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. P012C means the signal voltage is below its lower limit – typically a signal wire shorted to ground, an open signal or 5 V reference wire, or a failed sensor. GM's supercharged V8 sets it below 3 % of the 5 V reference (about 0.15 V), with 320 of 400 samples failing, continuously monitored; two trips are normal, one in some 2019 applications. FCA documented false settings on the 2019 Jeep Wrangler 2.0 turbo that were cured by a software update. A substitute value is used and power may be limited.

Likely causes

Connector unplugged or corroded, signal or reference wire open
Signal wire shorted to ground
Sensor failed internally
Control module software (false setting)
5 V reference shorted by another sensor

Symptoms

  • Check engine light on
  • Often no noticeable symptoms
  • Power limitation possible

Repair estimate

DifficultyEasyDIY possible
Parts and labour€20–250
Time0.3–1 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

turbocharger inlet pressure sensor asensor wiringsensor reference voltage

Related codes

P012AP012BP012DP012EP0107

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.