EngineLightCodes
Powertrain code

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

Severity
Fix soon
Typical repair cost
$40–$330
Do it yourself
Possible, easy
Shop time
0.3–1.5 hours

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.

How the engine computer detects it

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 (77 °F) deviation, Ford above about 17 °C (63 °F); 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 (151 °F) while driving. A detected block heater suspends the test. Two consecutive trips are needed.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

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

Common causes

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

How to diagnose P0111

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: intake air temperature sensor, intake air temperature sensor wiring, mass air flow sensor.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
1
Fuel and air metering
11
Specific fault

Questions drivers ask

Can I drive with code P0111?

Usually yes for a short time, if the car drives normally, the temperature gauge reads normal and the check engine light is steady. If the light flashes, the engine loses power or overheats, or other warning lights come on, pull over and have it checked.

Will my car pass an emissions inspection with P0111?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

Will P0111 clear by itself?

The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.

Can I fix P0111 myself?

Often yes, with an OBD-II scanner and basic tools. Difficulty: easy. Start with the cheapest checks before replacing expensive parts.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.