heavyduty Posted January 3, 2016 Report Share Posted January 3, 2016 Does anyone know is there a good way to test a voltage doubler on a fredomline transmission. It throws a sm code and audible alarm every once and a while mostly after it shifts in to 12 gear. I have done all normal things like cleaning all cables and grounds. If I pull codes on the trans ecm it gives 39 and E7. If I am looking that up correctly it says loss of communication between trans and shifter. Any thoughts would be appreciated. Link to comment Share on other sites More sharing options...
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