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?

Re: 08 Tahoe Hybrid Battery
 

Is there anyway I could PM you for a quick chat about a Yukon battery im working on?

Re: 08 Tahoe Hybrid Battery
 

I just replaced the batteries in my 2010 Tahoe Hybrid and now getting a ton of codes I cannot clear. These codes have locked out an engine start, so I am stuck. I was told I need to follow #PIT4808H, but I am having trouble determining if my OBDLink MX+ can perform the SEQ EBCM/HCP/ECM/TCM/BECM Sequential Programming called out. Below is a list of all the codes that I cannot clear. Any help is greatly appreciated!

HPCM-HybridPtCtrl ($7E1) U1888 Network Confirmed Manufacturer Defined
ECM-EngineControl ($7E0) P0AC4 PowerTrain Confirmed Manufacturer Defined
ECM-EngineControl ($7E0) P0AC4 PowerTrain Pending Manufacturer Defined
ECM-EngineControl ($7E0) U0109 Network Pending Lost Communication With Fuel Pump Control Module
ECM-EngineControl ($7E0) U0129 Network Pending Lost Communication With Brake System Control Module
HPCM-HybridPtCtrl ($7E1) U1875 Network Pending Manufacturer Defined
HPCM-HybridPtCtrl ($7E1) U1878 Network Pending Manufacturer Defined
HPCM-HybridPtCtrl ($7E1) U1888 Network Pending Manufacturer Defined
HPCM-HybridPtCtrl ($7E1) P0BBD PowerTrain Permanent Manufacturer Defined
HPCM-HybridPtCtrl ($7E1) U1888 Network Permanent Manufacturer Defined
HPCM-HybridPtCtrl ($7E1) U1875 Network Permanent Manufacturer Defined
HPCM-HybridPtCtrl ($7E1) U1878 Network Permanent Manufacturer Defined
ECM-EngineControl ($7E0) U0109 Network Permanent Lost Communication With Fuel Pump Control Module
ECM-EngineControl ($7E0) U0129 Network Permanent Lost Communication With Brake System Control Module

Re: 08 Tahoe Hybrid Battery
 

No. Make a thread.

Bad 12V battery.

Re: 08 Tahoe Hybrid Battery
 

I had the 12V battery disconnected during the hybrid batter change. I will try replacing the 12V battery tonight and see if the codes clear this time.

Re: 08 Tahoe Hybrid Battery
 

I just had the battery checked, and there were no issues found with the 12V battery. I still have all these codes.


ECM-EngineControl ($7E0)P0AC4PowerTrainConfirmedManufacturer Defined

HPCM-HybridPtCtrl ($7E1)U1888NetworkConfirmedManufacturer Defined

ECM-EngineControl ($7E0)P0AC4PowerTrainPendingManufacturer Defined

ECM-EngineControl ($7E0)U0109NetworkPendingLost Communication With Fuel Pump Control Module

ECM-EngineControl ($7E0)U0129NetworkPendingLost Communication With Brake System Control Module

HPCM-HybridPtCtrl ($7E1)U1875NetworkPendingManufacturer Defined

HPCM-HybridPtCtrl ($7E1)U1878NetworkPendingManufacturer Defined

HPCM-HybridPtCtrl ($7E1)U1888NetworkPendingManufacturer Defined

ECM-EngineControl ($7E0)U0109NetworkPermanentLost Communication With Fuel Pump Control Module

ECM-EngineControl ($7E0)U0129NetworkPermanentLost Communication With Brake System Control Module

HPCM-HybridPtCtrl ($7E1)P0BBDPowerTrainPermanentManufacturer Defined

HPCM-HybridPtCtrl ($7E1)U1888NetworkPermanentManufacturer Defined

HPCM-HybridPtCtrl ($7E1)U1875NetworkPermanentManufacturer Defined

HPCM-HybridPtCtrl ($7E1)U1878NetworkPermanentManufacturer Defined

Re: 08 Tahoe Hybrid Battery
 

The scope of systems covered by those codes screams 12V battery.

• Bad battery connection
• Bad main leads
• HV battery safety plug not inserted correctly (not locked in place - 3 steps - 1) insert, 2) lever it up vertically, 3) slide it down to lock) - but this should have its own code.
• You did something horribly, horribly wrong during the installation and broke stuff.

Re: 08 Tahoe Hybrid Battery
 

U1888 Lost Communication with Battery Pack
U0109 Lost Communication With Fuel Pump Control Module
U0129 Lost Communication With Brake System Control Module
U1875 Drive Motor A Control Module Lost Communication With Battery Energy Control Module
U1878 Drive Motor B Control Module Lost Communication With Battery Energy Control Module
P0BBD Battery Pack Variation High
P0AC4 Powertrain Control Module Requested MIL Illumination

The Electronic Brake Control Module and Fuel pump Control Module are both at one end of the high speed bus after the Battery Energy Control Module. My guess is that you did not plug in the multi-wire harness connector at the battery all the way in. If that happens, it will disconnect the battery, fuel pump, and brake system modules from the rest of the bus. That would account for the first 5 codes above.
https://cimg4.ibsrv.net/gimg/www.gre...6cdb69b7a1.jpg

For the P0AC4 code, that was set by the PCM to alert you of a problem by turning on the "check engine" light.

For the P0BBD code, it must be left over from before you replaced the battery. It is still stored in the Hybrid Powertrain Control Module. Since it has not been able to communicate with the battery module, it does not know that it is good now.

If you still have problems after verifying the connector is all the way in, I would suspect that the battery energy control module inside the high voltage battery has problems. Did you install a new or used/rebuilt battery? It could also be that the harness going to the module was not connected properly if it is a used/rebuilt battery.

Re: 08 Tahoe Hybrid Battery
 

After thinking thru everything I did during the battery change, I am thinking I did not get some of the connectors together properly. I had quite a bit of trouble getting the main connector back together. I didn't want to force it and break something. It just didn't feel like it would click in place. I will go back thru and check all my connectors and double check the safety plug and voltages.

FYI
I removed the individual batteries and installed new batteries. Which by the way is a lot more tiny bolts than I found in any online descriptions or videos, but still not that hard overall.

Thanks for all the suggestions guys. I will update after I have double checked everything.

Re: 08 Tahoe Hybrid Battery
 

You need to go back several steps.

Are you in Oklahoma?

Did you replace the modules with the sh!tty Chinese modules? If so, don't expect them to last. I purchased and evaluated 5 of these (state that you're going to test them, and it ensures you get the cream of the crop), and MOST 10+ year old Gen2 Prius modules are better. They use some dirty tricks to make their modules appear very good when new, but they deteriorate VERY rapidly.

Second, regardless of what you used, did you torque all 80 terminal nuts to 48 in-lb? If not, you need to do it. Too loose, and you'll get high resistance, heat, voltage drop and likely block deviation error codes. Too tight, and you risk snapping off the terminal stud. I don't remember how the main connections are made to the relays, but if they're nuts on studs, same thing applies. If they are 8mm hex head/5mm thread, it's 48 in-lb. If they are 10mm hex head/6mm thread, it's 60 in-lb.

If you don't have a quality torque wrench that can reliably produce those torques, get one.

Re: 08 Tahoe Hybrid Battery
 

I am in San Diego, CA.

I got my batteries from https://www.electronautomotive.com/

I will double check the torque on all of the terminal nuts while I am looking at connector plugs.

Re: 08 Tahoe Hybrid Battery
 

After a thorough inspection, I did not have the main connector shown in the picture above plugged in correctly. I fiddled around with it and got it all plugged in correctly, and all codes were resolved.

Thanks for all the advise troubleshooting this silly issue. It finally runs and drives great again!

Re: 08 Tahoe Hybrid Battery
 

You didn't indicate if you had checked the torque on the terminal nuts. It is critically important that they be 48 in-lb. Too loose, and they will produce way more heat than they should. It will contribute to premature failure. Improper installation will likely void your warranty, and now there is a public record thereof.