reduced power hard tranition from gass to electric jerky transition as well as the avove .multiple codes popping up some the same over and over . then its fine for half a day or even two day then it starts all over again
i atatcged pict pf the codes .any idea on where to start .
jimr5454@yahoo.com

 

12V battery

 

Lots of communication faults. Wiring?

 

these codes come up over and over the same 2 so i beleive its the auxilary trans pump which i am intalling a new one today.228000 ish miles on truck .
any thought. $347 for pump and 87 for harness before discounts.

 

Jim5454 Was the aux trans pump your problem? Just glancing at the codes it appears that the electronic circuits are resetting possibly due to a voltage drop like what might happen with a bad 12V battery?

 

it did help for a week or so but ultimatly it was a waste of time .the computer that controlled it ended up being bad.fixed that and ran great

 

Thanks for letting everyone know. Not a lot of traffic here in the GM Hybrid trucks section, I guess these GM Hybrids are not quite as common as some other hybrid vehicles out there? The latest technology seems to have moved away from the transmission based Two mode Hybrid I think? Probably due to the complexity and the very expensive manufacturing cost? My 2018 GMC Sierra Crew Cab/Std Bed Denali Ultimate 420hp 6.2 0 to 60 5.4 seconds MSRP 64k weighs about the same as this 09 Tahoe original MSRP 54k The Denali is averaging over 21.5 mpg over the last 6000 miles. Technology keeps moving forward and the non-economical solutions are simply left behind I guess. I still like the old HyHo and I bought this sucka dirt cheap, it makes a perfect daily driver "beater" vehicle and looks darn good doing it. All I need is some blue underbody lighting (pimp my ride) and I will be Young and Cool again "yeah right" Hahahahahaha


This old Tahoe Hybrid makes me smile every time I jump in in to drive off.....................