Powertrain, generic · Fuel and air metering

P0112 Intake Air Temperature Sensor 1 Circuit Low Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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. 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). Documented limits: Ford petrol 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, as a substitute and limit torque.

Likely causes

Signal wire shorted to ground (chafed insulation)
Sensor shorted internally
Moisture or corrosion in the connector
Engine control module faulty

Symptoms

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

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–250
Time0.3–1.5 h

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

What to check first

  1. Check reading on a cold engine
  2. Inspect harness for shorts to ground

Parts involved

intake air temperature sensorintake air temperature sensor wiringmass air flow sensor

Related codes

P0110P0111P0113P0114P0097

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