EngineLightCodes
Powertrain code

P0112 Intake Air Temperature Sensor 1 Circuit Low Bank 1

Severity
Fix soon
Typical repair cost
$30–$280
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. P0112 means the signal is below its valid range. With an NTC sensor that points to a short to ground in the signal wire or an internally shorted sensor, and the control module would read an implausibly hot value (GM about 150 °C (302 °F)). Documented limits: Ford gasoline below 0.244 V for 5 s, Ford diesel below 0.10 V, GM below 62 ohms. The circuit is monitored continuously; GM needs two trips. Some systems then use the coolant temperature, capped at 40 °C (104 °F), as a substitute and limit torque.

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

Symptoms

  • Check engine light on
  • Usually hardly noticeable
  • Retarded ignition, reduced power or torque limit on some systems
  • Harder cold start possible

Common causes

  1. Signal wire shorted to ground (chafed insulation) Most likely
  2. Sensor shorted internally Most likely
  3. Moisture or corrosion in the connector Possible
  4. Engine control module faulty Less likely

How to diagnose P0112

  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
12
Specific fault

Questions drivers ask

Can I drive with code P0112?

Drive gently and only as far as you need to. The engine computer may limit power to protect the engine, so avoid highways and heavy traffic until it's fixed. If the check engine light starts flashing, pull over.

Will my car pass an emissions inspection with P0112?

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 P0112 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 P0112 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.