Powertrain, generic · Fuel and air metering

P0127 Intake Air Temperature Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0127 is not a circuit fault but a functional check of the air path: the measured intake air temperature is too high for the operating state. The logic is documented for a Bosch EDC16 diesel (Saab 9-3): if the intake air exceeds 130 °C and does not fall below it within 45 s after the exhaust gas recirculation valve is closed, hot exhaust gas is evidently still entering or the sensor is wrong. The engine then disables EGR and runs in limp mode with reduced torque. GM has the code in its diesel software but disabled for US OBD II; Ford reports an overly hot intake air reading as P0111 instead. On other engines a hot reading can also come from warm under-bonnet air being drawn in.

Likely causes

EGR valve stuck open or not sealing (diesel)
EGR cooler clogged or bypass flap stuck in bypass
Charge air cooler dirty or airflow through it blocked
Sensor reading wrong, or hot engine-bay air drawn in (loose intake duct)

Symptoms

  • Check engine light on
  • Loss of power, limp mode with torque limit
  • EGR switched off
  • Knock tendency and retarded ignition on petrol engines

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–1,200
Time0.5–4 h

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

Parts involved

intake air temperature sensoregr valveegr coolercharge air cooler

Related codes

P0111P0112P0096P007BP2457P0401

References: law.cornell.edu, saabwisonline.com, gsi.ext.gm.com.