tjrob2000 wrote: ↑
Tue Dec 15, 2020 7:59 am
My apologies if I misunderstood the way this fix has been described. The video I saw states the system doesn't charge for 8 mile, which makes it sound like they are saying it's designed that way. Thanks for your clarification. Also, I didn't mean to imply it would over charge the battery. I understand the disconnecting of the control signal just makes it no longer a smart system. I appreciate your input and I've wondered about the IPDM being a possible cause (and perhaps it still is). If it pops back up then I'll try this fix.
No worries, no apology needed. The problem is, IPDM's are expensive and no one can say whether it will fix the issue. The determinate "voltage reading" comes to the IPDM from the ECM via CAN, and the current consumption on most versions similarly comes from the BCM. The alternator doesn't directly report its output a la Ford, the ECM and BCM need to infer its performance from the sensors. So there are multiple possible error sources. For the engineers, chasing a finite analysis is a bit like the old Peter Principle corollary that if more than one person is responsible, no one will be at fault. Chances are it's an issue called "cumulative tolerance", where the +/- tolerances for all the components cancel out on average, but a small percentage of vehicles have components that are all off in one direction and add up to a problem. Like I said, the issue has spanned many years on many models, so if there was an easier answer they would have found it long ago.