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.
Low severity. Can I keep driving?Yes, you can normally keep driving and take it to a repair shop when convenient.
Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.
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
Most 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
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: easy
- It affects emissions.
What each character of P0111 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 1: Air and fuel
- 11: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0111?
Yes, you can normally keep driving and take it to a repair shop when convenient.
What causes code P0111?
The most common causes are: 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.
Related codes
- P0112Intake Air Temperature Sensor 1 Circuit Low Bank 1
- P0113Intake Air Temperature Sensor 1 Circuit High Bank 1
- P0114Intake Air Temperature Sensor 1 Circuit Intermittent/Erratic Bank 1
- P00CEIntake Air Temperature Measurement System - Multiple Sensor Correlation Bank 1
- P0096Intake Air Temperature Sensor 2 Circuit Range/Performance Bank 1
- P011BEngine Coolant Temperature/Intake Air Temperature Correlation
Sources
- law.cornell.edu: 13 CCR 1968.2
- newtonnet.co.uk: fordobd2012
- gsi.ext.gm.com: 18OBDG04 Engine Diagnostics
- gsi.ext.gm.com: 16OBDG03 Engine Diagnostics
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.