08 Tahoe Hybrid Battery
 

So, I've had a small onslaught of issues lately with the Tahoe, but the other day I got codes P0BBD and P0AC4. So I have the torque app and downloaded the pids for GM to see the hybrid battery voltages and soc. Took it on a 2 hr trip, highest soc was 70% and lowest was a 50%. Battery power can last up to 8 to 10 blocks. Light never came back on after I cleared it. Is there anything in particular I should be looking for in these values that I get from the computer?

Re: 08 Tahoe Hybrid Battery
 

Log all 20 voltages during auto-stop by discharging the battery with all available electrical accessories (A/C, lights, rear defroster, etc.).

Re: 08 Tahoe Hybrid Battery
 

To fully charge the battery by turning on tow mode this will shut off EV mode... you should consider using only tow mode tell you have enough saved for a new battery.. as it might be on it's way out
it will also turn off the Auto Stop..


because the big battery Starts the engine up via the 60,000 Watt electric engine starting motor.. It needs OVER 9000!!! watts of power to turn over the engine (it's a high speed start 1,500-2,000RPM so it can be synchronized with the auto stop speed i.e driving at 0 to 30mph )
it does not have a normal 12vDC starter..


Have you been having sluggish starts???


I suggest to disable auto stop but turn off tow mode when running higher speeds over 35MPH this way you don't burn up whats left of the battery once you get to 35mph or less, turn on tow mode the keep the ICE running to avoid Auto stop


Auto stop is very hard on the battery and draws a lot of power to start the engine...

this should get you a bit more time tell you can buy a battery with in the next year

Re: 08 Tahoe Hybrid Battery
 

Perspective:

Auto-stop is not "very hard on the battery." The load depends on the accessories being used, but it is rarely more than 4000W and that is if you're running ALL accessories with the A/C on full blast.

9000W of power is... 12 hp

Not particularly alarming and not at all hard on an HV battery unless it is severely deteriorated.

Re: 08 Tahoe Hybrid Battery
 

Steve, PM me regarding some tech info if you can sometime.

Re: 08 Tahoe Hybrid Battery
 

I have been having a load of issues
random electrical issues

today on a cold start it refused to move then I popped it into M4 and I was on my way...

All solved by..
Shifting to M4 fixed it after driving a mile in M4,

All functions were normal again for me Auto Stop auto start regeneration.... smooth acceleration and smooth slow downs( coasting to capture rengen power)

fine with a few warm starts as well I'll see what happens later today

yes the air intake is clean I did it about 1000 miles ago

Re: 08 Tahoe Hybrid Battery
 

The starts are fine, engine starts good, its just randomly it will "stall" from a dead stop, but not in hybrid mode, only when running in pure gas mode. Every time in EV mode it goes from a stop just fine, and if its w warm day and Ive been driving a lot i can go quite a few blocks on EV mode

Re: 08 Tahoe Hybrid Battery
 

https://cimg9.ibsrv.net/gimg/www.gre...1c00412437.jpg
https://cimg2.ibsrv.net/gimg/www.gre...fe308912e0.jpg
this was from driving today, mil illuminated and this is a snapshot of the hybrid battery, it clearly looks like the cells in the middle are bad?

Re: 08 Tahoe Hybrid Battery
 

Nope. Unless by "middle" you mean the middle 38 and probably one of the ends, then yes. The 0.5V difference between the first two blocks is also indicative of failure/weakness.

Time for a new battery.

Re: 08 Tahoe Hybrid Battery
 

Bullocks, that's what I was afraid of. No point in swapping any cells, just do the whole thing?