Powertrain, generic · Fuel and air metering

P012D Turbocharger/Supercharger Inlet Pressure Sensor A Circuit High

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. P012D means the signal voltage is above its upper limit – typically the signal wire shorted to the 5 V reference or battery voltage, or an open sensor ground that lets the signal rise to the reference. GM's supercharged LT4/LT5 sets it above 97 % of the reference (about 124 kPa) with 320 of 400 samples failing, monitored continuously; two trips on the LT4, one on the 2019 LT5. FCA documented false settings on the 2019 Jeep Wrangler 2.0 turbo, fixed by new engine software. The control module substitutes a modelled or ambient value and may limit boost.

Likely causes

Signal wire shorted to 5 V reference or battery voltage
Sensor ground open or connector corroded
Sensor faulty internally
Control module software (false setting)

Symptoms

  • Check engine light on
  • Reduced power or limp mode possible
  • Often no noticeable symptoms

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–300
Time0.5–2 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

P012AP012BP012CP012EP0238P0108

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