Intake Air Temperature Circuit Low Input Bank 1
The intake air temperature (IAT) sensor is reporting a voltage signal that is lower than the engine computer's expected range. This sensor measures incoming air temperature to help the engine adjust fuel mixture and ignition timing; a low signal typically indicates a faulty sensor or wiring issue.
What You Might Notice
- Check Engine Light illuminated
- Engine pinging or knocking under acceleration
- Rough idle or stalling
- Poor fuel economy
- Difficulty starting in cold weather
Most Common Causes
- 1
Faulty IAT Sensor
The intake air temperature sensor itself is internally damaged, shorted, or has failed internally. This is the most common cause of P0112 codes.
- 2
Corroded or Damaged Wiring
The wiring harness or connectors leading to the IAT sensor are corroded, loose, or damaged, causing low voltage signal transmission to the engine computer.
- 3
Poor Connector Contact
The sensor connector has loose pins, corrosion, or improper seating that prevents proper electrical connection between the sensor and the vehicle's wiring harness.
- 4
Engine Control Module Issue
In rare cases, the ECM itself may have an internal fault or ground issue causing it to misinterpret a normal IAT sensor signal as low voltage.
How to Diagnose It
- 1
Check Faulty IAT Sensor — The intake air temperature sensor itself is internally damaged, shorted, or has failed internally. This is the most common cause of P0112 codes.
- 2
Check Corroded or Damaged Wiring — The wiring harness or connectors leading to the IAT sensor are corroded, loose, or damaged, causing low voltage signal transmission to the engine computer.
- 3
Check Poor Connector Contact — The sensor connector has loose pins, corrosion, or improper seating that prevents proper electrical connection between the sensor and the vehicle's wiring harness.
- 4
Check Engine Control Module Issue — In rare cases, the ECM itself may have an internal fault or ground issue causing it to misinterpret a normal IAT sensor signal as low voltage.
How to Fix It
- 1
Replace IAT Sensor
Remove the intake air temperature sensor from the intake manifold or air intake tube and install a new OEM or equivalent replacement sensor. Ensure proper seating and secure all fasteners.
- 2
Inspect and Clean Connections
Disconnect the IAT sensor connector and inspect for corrosion or debris. Clean contacts with electrical contact cleaner and reconnect firmly, or replace the connector if damaged.
- 3
Repair Wiring Harness
Inspect the wiring harness from the IAT sensor to the engine control module for breaks, cuts, or corroded sections. Repair damaged wiring with appropriate gauge wire and quality connectors, or replace the entire harness if extensively damaged.
- 4
Clear Code and Verify
After repairs, use a diagnostic scanner to clear the P0112 code and perform a road test to ensure the sensor reads appropriate temperatures and the code does not return.
Need a deeper diagnosis?
Search for related repair guides or browse by system.