P0110 Intake Air Temperature Circuit Malfunction

DTC P0110 is a trouble code with the description “Intake Air Temperature Sensor Circuity (Bank 1)”, and it is set when the PCM (powertrain control module) realizes the signal coming from the IAT (intake air temperature) sensor circuit is giving bad readings. In other words, the signal coming from the IAT sensor is not a match to factory specifications and something is wrong.

Recommended Scanner with Live Data: ANCEL FX2000

Some Background Information on the Intake Air Temperature Sensor

The IAT sensor measures air temperature by observing and detecting resistance in the air, and it’s usually located in the air filter duct housing. However, the IAT sensor is often located in the intake manifold – and in some cases it’s into the mass air flow sensor. It’s a two-wire sensor that has a ground wire, and a 5 volt reference wire coming from the PCM. That reference wire is also the acting signal wire.

When the air is warmer, the resistance is lower and so the signal voltage will read lower. When the air is colder, the resistance and voltage are higher. A good scanner with live data may show these readings for you.

The PCM uses data from the IAT sensor so it can properly handle ignition timing and fuel control, making it a vital component for a smooth-running engine.

DTC P0110 is a generic trouble code, but it can help you get pointed in the right direction. Simply find out where the IAT sensor is located in your vehicle, as every vehicle will require a slightly different means of repair.

When the IAT sensor sends a signal that is out of the normal operating range, you’ll get the diagnostic trouble code P0110. Ford, Toyota, Lexus, Mercedes Benz and Nissan vehicles are more likely to run into this trouble code, with the Nissan Maxima being one of the most common vehicles to see this code.


There usually aren’t any symptoms associated with this trouble code, other than a check-engine light. In some cases, it may have an impact on your vehicle’s fuel consumption. Since your vehicle uses data from the IAT sensor to control the fuel and ignition timing – it can make the engine run rough as the system is confused by the improper sensor readings.

What Causes the P0110 Trouble Code?

  • Faulty MAF sensor
  • Faulty IAT sensor
  • Bad PCM
  • Circuit issues
  • Damaged or loose sensor connection

How to Fix

First, use an OBD-II scanner to reset the trouble code and then do a test drive to see if the code comes back. If the code comes back, then you have a problem you need to address.

However, if the code sets again and the check engine light comes back on, then you’ll need to take it a step further. Next, you can use a scanner with live data to watch the IAT sensor input voltages that PCM is reading. If you notice the input voltages are not proper then you’ll need to replace the IAT sensor.

Before buying the part and getting ahead of yourself, you can pop the hood, locate the sensor, and make sure the wiring and connection is in good shape.

Clear the code. Unplug and re-connect the sensor to start a fresh new connection. Run the vehicle. If the code comes back then change the sensor. For some vehicles, the IAT sensor is built into the MAF sensor – and you’ll have to replace that.

Make sure to thoroughly check the connections and wiring before replacing the sensor. Otherwise you will end up with the code again – and less money in your pocket.

Related OBD-II Codes: P0111, P0112, P0113, P0114

Here’s an awesome video by CarsNToys that teaches you how to test your IAT sensor without an expensive scanner. The video performs the testing on a 1997 Nissan Maxima… and like we said at the beginning of this article – this code is a common issue for those cars.