ECMlink Won't read GM IAT Sensor

[Justin Miller]

I am setting up for Speed Density. I am using the plug and play SD harness from MAF plug to a GM 4 bar map and GM IAT. The IAT reads -40 all the time. Has anyone ever experienced this?

 

[Vegas Smith]

Either it's a bad sensor or bad wiring. Obviously settings need to be correct too.

 

[We're on Boost]

The GM and AEM IAT sensors are "the same" according to everybody, so you can use AEM specs if you want to check the sensor resistance at a certain temperature. (See below)

-40 C is the lowest the sensor will read, and that is when the sensor resistance is very high, like 100,000 ohms. They don't even go that far on the chart for the 1/8" sensor but they do for the 3/8" sensor, and their charts are about the same otherwise. Anyway very high resistance, well an open circuit (not actually connected) is very high resistance, so that's one possible way that you'd get -40 C.

If you want to do the easiest and most basic check for your sensor accuracy, just take the electrical plug out of it when the whole thing is sitting there at "room" temp and measure the resistance between the 2 terminals with a multimeter. It should be 2230 ohms at 86 F for example.

Here's the AEM chart for resistance vs temp:

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I don't even have one of these things. I'm just shooting from generally knowing how stuff works. So I don't know the setup part of it in ECMlink.

 

[99dsmer4g63]

You may want to post a log so we can see your settings.

-Daniel