P0112 moderate

Intake Air Temperature Sensor 1 Circuit Low Input

What does P0112 mean?

The P0112 code means the vehicle's onboard diagnostic system has detected: Intake Air Temperature Sensor 1 Circuit Low Input. This is a moderate severity code.

Common Symptoms

  • Check Engine Light on
  • Engine may run rich
  • Possible hard starting when warm
  • Minor performance issues

Probable Causes (Ranked by Likelihood)

  • IAT sensor shorted internally causing low voltage Very High
  • Short to ground on signal wire High
  • Failed sensor reading stuck at extreme cold temperature Moderate

Step-by-Step Diagnostic Procedure

  1. Check IAT voltage: at room temperature should be about 2-3V. Below 0.3V indicates a short.

  2. Disconnect the IAT sensor. If voltage rises to 5V at the connector, the sensor is shorted internally.

  3. Inspect wiring for shorts to ground.

  4. Replace sensor if confirmed faulty.

Frequently Asked Questions

What temperature does a low IAT input simulate?

A shorted IAT circuit typically reads at the extreme cold end of the sensor range, often -40F or below. This causes the ECU to think the air is extremely cold and may add excess fuel.

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