Medium and Heavy Trucks
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Hi my name is***** will be glad to try to help. First let me be sure I understand correctly.... Your current truck you swapped ECMs with the truck you sold which had moisture issues? So you kept the faulty ECM and put your good ECM on the truck to sell it?
I recommend having your ECM reflashed if the problem never existed before the swap and all your connector pins look good as well as the harness. It sounds like it has to be a software issue if nothing else was done besides the ECM swap. Let me know
Thanks for the info. If the ECM had problems from moisture it is likely that there is corrosion internally that is now showing up with this problem you are having now. It is possible it is shorting this part of the circuit. Reflashing the ECM will help confirm if it can be resolved with the software and if not you will be replacing this ECM. You can have the ECM bench tested and reflashed.
It is also possible that the ECM might be condemned on the bench test and attempted reflash.
When you put the ECM back on a different truck? Or you remove the ECM and after reinstallation the problem is gone temporarily?
Thanks for the info. I would take a close look at the harness for corrosion and bare wiring. If ok and since you still have access to the sold truck check and see if the temp inputs and outputs are on the same pins for both trucks just to be sure. There should be 5v signal out and then the ECM reads the return voltage. Make sure you have good 5v signal as well.