P0112 Intake Air Temperature (IAT) Sensor Circuit Low Voltage

Hello,

I have a 1999 jeep cherokee sport with a 150,000 miles.

My wife said the problem started last year, the Check engine light would come on after it rained but then go off.

Now it is on all the time and I failed inspection.

I changed the Intake air temperature sensor with a new one and reset the computer many times, and the same code keeps turning on the check engine light after driving a few miles. I tried two brands of sensors so I do not think it's the sensor.

A mechanic checked it out, and said he checked the electrical connections, and believes its the ECM.

Should I buy a used ECM from a Junk Yard and put it in and reflash it, or try something else.



Thank you

Please any advice would be appreciated...

Did you check for current to the sensor with a voltmeter?

Yes the mechanic checked that, he said he did a full electrical check on the sensor.

That kind of sounds like an assumption to me. What was the voltage? Have you cleaned the connections at the ECM? See, the problem is the mechanic can't make any money cleaning connections. He needs to replace expensive parts.

I have not cleaned the connections at the ECM.

I am not sure if the mechanic did either, I could try a good spray cleaner like DeoxIT D5 Connector & Contact Treatment, and see if it helps.

Thanks