I also had this problem. It ended up being my "Skid" module. Replaced with a used one off ebay for $50.
Of course before doing this I checked all wiring going to the rear (there is a plug connecting the 2 rear to the front).
Which chain kit did you buy? Ah - I see, Cloyes! I'm doing a head gasket and trying to decide if I should replace the timing chain while I'm at it. Definitely not going to spend ~$1000 on OEM.
My head gasket is also leaking, 2004 V6. I'm about 1/3 of the way through on the replacement trying to decide if I want to replace the timing belt. There is this awesome YouTube video that is making it way easier!
YouTube