Powertrain, generic · Fuel and air metering

P012E Turbocharger/Supercharger Inlet Pressure Sensor A Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The turbocharger/supercharger inlet pressure sensor A sits ahead of the compressor – between air filter and turbocharger, or on GM's supercharged V8 between throttle and supercharger. It is an analogue 5 V pressure sensor used for the compressor pressure ratio, filter restriction and cross-checks with the other pressure sensors. P012E covers a signal that jumps or drops out briefly without staying below or above the circuit limits – typically a loose contact. Such intermittent monitors usually count short limit violations or changes faster than real pressure can move. No manufacturer document using exactly this code was found: GM handles jumps of this sensor through its range check P012B and the counting windows of P012C/P012D, and Ford's 2023 diesels report their digital sensor under P012A. The description therefore rests on CARB's circuit monitoring requirement and component information. A substitute value is used while the fault is present.

Likely causes

Loose contact or corrosion at the sensor connector
Broken or chafed wire making intermittent contact
Sensor faulty internally (erratic output)
Control module or software

Symptoms

  • Check engine light on
  • Occasional power reduction or boost fluctuation
  • Often no noticeable symptoms

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–300
Time0.5–2.5 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

P012AP012BP012CP012DP0239

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com, patents.google.com.