How much does it cost to fix P0112?

DIY repair typically costs $10–$40 for parts. Professional repair runs $75–$200 including parts and labor.

P0112

Powertrain

Low

Intake Air Temperature Circuit Low Input

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The P0112 code is set when the engine control module (ECM) detects that the voltage signal from the Intake Air Temperature (IAT) sensor is lower than expected — typically below about 0.5 volts. Because the IAT sensor is a negative temperature coefficient (NTC) thermistor, low voltage corresponds to low resistance, which means high temperature. So the ECM thinks the intake air is extremely hot (often 250°F+ or more), even when it clearly isn't. This causes the ECM to lean out the fuel mixture, since hot air is less dense.

In practice, the engine may actually run slightly rich because the ECM's other correction strategies (like O2 sensor feedback) detect the mismatch and compensate. The most common cause is a failed IAT sensor with an internal short, followed by a wiring short to ground. Water or moisture in the connector is another frequent culprit, especially in areas with high humidity, heavy rain, or after a car wash or engine cleaning.

This code is low severity on most vehicles. The ECM will default to a substitute temperature value and continue operating with only minor driveability effects. You can drive safely with this code, but you should plan to fix it within the month. The IAT sensor is one of the least expensive sensors on the engine, and replacing it is typically a quick and easy job. Check the connector for moisture first — sometimes simply drying it out and applying dielectric grease resolves the issue entirely.

Severity

Low — MonitorThis Month

Symptoms

•Check Engine Light is on
•Engine may run slightly rich
•Minor decrease in fuel economy
•Slight hesitation or stumble on acceleration
•Engine may idle slightly higher than normal
•Black exhaust smoke in severe cases

Likely Causes

Faulty IAT sensor shorted internally35%

The IAT sensor's thermistor can develop an internal short, causing it to report extremely low resistance (high temperature) regardless of actual air temperature, pulling the signal voltage low.

Short to ground in IAT sensor wiring25%

If the signal wire in the IAT circuit contacts a ground point due to chafing or connector damage, the ECM sees a low voltage that mimics an extremely high temperature reading.

Corroded or water-damaged connector20%

Moisture intrusion into the IAT connector can create a partial short between signal and ground pins, reducing the voltage to below the expected range.

Wiring harness damage near heat source10%

Wire insulation melted or damaged near the exhaust manifold or other heat source can cause the signal wire to short to the shielding or adjacent ground wire.

Aftermarket intake or filter modification10%

Aftermarket cold air intake installations sometimes route the IAT sensor wiring poorly or use incompatible connectors, leading to grounding or signal issues.