Powertrain, generic · Fuel and air metering

P0111 Intake Air Temperature Sensor 1 Circuit Range/Performance Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Intake air temperature sensor 1 is the first air temperature sensor in the intake path; depending on the vehicle it is built into the mass air flow sensor, mounted near the air filter or, on some naturally aspirated GM engines, fitted in the intake manifold. Most versions are NTC thermistors in a 5 V divider: the hotter the air, the lower the signal voltage. P0111 is a plausibility fault: the signal is electrically valid but does not fit. The usual test runs at key-on after a long soak (Ford 6 h, GM 8 h): the intake air sensor is compared with other temperature sensors such as coolant, cylinder head, charge air cooler or IAT2, which should all read about the same. GM flags it above about 25 °C deviation, Ford above about 17 °C; Ford first confirms with a drive above 40 mph because sunshine can warm a sensor, and also sets P0111 if the air reads over 66 °C while driving. A detected block heater suspends the test. Two consecutive trips are needed.

Likely causes

Sensor drifting or stuck at one value (ageing, oil from crankcase ventilation)
Contact resistance at connector or wiring distorts the reading
Comparison sensor (coolant, IAT2, charge air cooler) wrong
Undetected preheater, heat soak or sensor mounted near a heat source

Symptoms

  • Check engine light on
  • Usually no noticeable symptoms
  • Slightly changed idle, power or cold start possible
  • Code often returns only after an overnight soak

Repair estimate

DifficultyEasyDIY possible
Parts and labour€40–300
Time0.3–1.5 h

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

Parts involved

intake air temperature sensorintake air temperature sensor wiringmass air flow sensor

Related codes

P0112P0113P0114P00CEP0096P011B

References: law.cornell.edu, newtonnet.co.uk, gsi.ext.gm.com, gsi.ext.gm.com.