General Code 13 IAT

[SrKegler]

I just replaced the ECU. That cleared up most of the problems on my car. At least it starts easily and runs great. I just have this annoying code 13 which is supposed to be the Intake Air Temp. My logger gives me a value of -75 deg for this one. Can't remember where I found it but one of my searches says this reading points to bad sensor grounds.

I've tried 3 different MAFS, still get the same code. Checked the ECU visually, can't see any problems there.

Other than the CEL being on, I'm not having any problems with the car. Give me some ideas on what to try next please.

 

[jeffo]

A reading of -75* indicates that the IAT circuit is completely open, no resistance to ground. Most often its caused by bad splices where guys do a 2G-to-1G MAS conversion. Have you traced the wire the whole way to the MAS, to make sure it isn't cut or open somewhere? You can also try grounding the IAT wire under the hood, and see if the logger reading goes way high.
Its also possible that the ECU that you bought has acid damage, which has caused a trace on the board to be open between the rear connectors and the circuitry.
If you have an ohmmeter, you can test the IAT sensor. If I recall it should read a few thousand ohms at room temperature. It is simply a thermistor that is connected between the GROUND and IAT pins of the MAS.