Well, to be fair, I didn't really drive it very long to give it a good solid charge after cleaning the terminals. May be a moot point, now, though. Either I need to clean more connectors, or get the dealer to flash the HCM and TCM.

 

UGH!!! Just got FIVE codes for the first time!!! B2AAA, P0420, P0430, and our favorites, P061B and P0AC4.

WHY CAN'T A DEALER FIGURE THIS OUT???

 

S Keith when the dealership tested my hybrid battery last year at this time the SOC was 52%. My Yukon also will not stay in auto stop for more than a few minutes with the A/C running. Actually, living in SW FL my mpg drops to 16 in the summer when I use the A/C system a lot more heavily. I work in the field and will sit with the A/C running to keep the car cool while I return phone calls. In the winter months when the temp goes down slightly I can milk 18 mpg's out of my Yukon. Never have I been able to get 19-20 mpg. My Yukon is a 2009 with 120,700 miles & I've owned it for 4 years.

 

I'm frustrated beyond belief. I felt like just starting a brand new thread to deal with this, but, no, it's still the same issue.

Here's the timeline so far:
February 2017 - I buy a 2008 Hybrid Tahoe. Seems to run fine, but for a few bumps and squirts. Eventually, I start seeing the dreaded PA061B and PA0AC4 codes. No one seems to be able to diagnose.

April 2017 - After pretty much ignoring the PA061B and PA0AC4 codes, I get a P0308 code. I take it to the dealer, and after nearly $500 of diagnostics, they want to either have me spend $9K on an engine replacement or $5K on replacing the lifters. I take the car to an independent mechanic who replaces the lifters for $1,600. He did NOT replace the camshaft. PA061B and PA0AC4 codes continue to pop up every now and then.

July 2017 - I take it to a DEALER in North Carolina who can't find anything wrong with the hybrid battery or system. Thinks that it's loose connectors. Cleans them and sends me on my way. Car runs better than ever before - for about two months.

September 2017 - Labor Day weekend, I'm driving and I notice a flashing engine light with a correlating feeling that I'm riding on rumble strips. Code spits out P0306. Take it back to independent mechanic who kept it for 6 weeks, lapping the valves and this time really replacing the cam and replacing all the lifters and gaskets again. Another $1600.

October 2017 - After mechanic declares that the car is running better than ever before, it's got an obvious dead miss without throwing a code. It has stalled 3 times throwing PA061B and PA0AC4 again.
I'm going to take it to the dealer on Friday. I already talked to them today, but they don't want to just diagnose "everything" - they want to be led. From what I've gathered in this room, I don't know where to start. Do I have them tackle the misfire, or could the ECM be causing a misfire because it wasn't reprogrammed after the camshaft work? Do I have them just go after the codes? Do I have them check the wiring? Connectors? Control modules? These mechanics have no CLUE where to start working on this thing, and at $115 PER DIAGNOSTIC, I'm gravely concerned.

 

Do you mean P0AC4 and P061B? Based on your other posting, it's pretty evident that you have a severely degraded HV battery. While I wouldn't expect that to generate misfire codes, it can definitely contribute to "shuddering" at lower rpm if it's engaging the electric drive motors, seeing an expected drop in voltage, cutting motors, seeing voltage rise, engaging motors, etc.


Concerning P030X codes, have spark plugs and ignition coils have been replaced at some point to address misfires?


Until you get to the bottom of your hybrid battery issues, you're likely chasing your tail.