Intake Air Temperature Sensor (IAT)

Description

The intake manifold air temperature sensor is installed into the rear of the intake manifold with the sensor element extending into the air stream. The IAT provides an input voltage to the Engine Control Module (ECM) indicating intake manifold air temperature. The input is used along with inputs from other sensors for intake air heater element operation, for engine protection, fuel timing and fuel control. As the temperature of the air-fuel stream in the manifold varies, the sensor resistance changes. This results in a different input voltage to the ECM.

IAT Sensor Cleaning & Location

This cleaning process is normally for Dodge Cummins that have exhaust brakes installed. But there has be a few reports of IAT sensors being dirty without a exhaust brake install. There is no maintenance schedule for cleaning the IAT sensor. If you do have a exhaust brake I suggest every oil change you clean the sensor. I clean mine every 6,000 miles and do a oil change at the same time.

IAT and MAP sensor locations Tools needed to remove the sensors

Ok. first thing when need to know is where is the darn IAT sensor located at. It's on the driver side of the engine towards the back of the head up against the firewall. Now you need the proper tool to remove it. You need a 13/16 deep well socket to remove the IAT sensor. Also your going to need a 6' extension. Preferably 3/8" drive. 

Location of the IAT sensor After 6K miles with a exhaust brake

Here is the location again with the socket and extension in place. Here is what the sensor looks like when its dirty. Now all you got to do is give it a few sprays of carburetor cleaner to remove the oily coating.

After a bit of solvent to clean them up

Now that they are cleaned. Just reverse the process to install them back in the manifold.

To test the IAT sensor you'll need a DVM (Digital Volt Meter) set it on the OHM setting. Now touch the black and red probes of the DVM to the two contacts inside the plug of the IAT sensor. Now compare the valves to the ones in the table. 

 

 

IAT Sensor Cleaning with Naptha (Coleman Stove Fuel)

IAT Sensor Resistance Values

Temperature Resistance
13°F 56K ohms
30ºF 40K ohms
32ºF 30K - 36K ohms
76ºF 13K ohms
77ºF 9K - 11K ohms
81ºF 6.87K ohms
122ºF 3K - 4K ohms
130ºF 4K ohms
167ºF 600 -675 ohms
212ºF 600 - 675 ohms

Replacement Sensor Part Numbers

Dodge 05014197AA
Cummins 3408345

 

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IAT Sensor