Service hybrid system message with no CEL
 

Alright so about 3 weeks ago my well maintained 2013 Tahoe Hybrid with 128k on the clock started throwing the Service Hybrid System message in the cluster. I have driven it a few weeks and the message has become more frequent. No CEL displayed and no stored CEL per my code reader. Auto stop mode still works at lights or while sitting but it seems to kick into the gas motor faster with any throttle input.
I used to be able to roll thru my neighborhood in auto stop or golf cart mode, now it seems to kick in to gas mode ASAP. Mileage seems pretty normal, if down it’s very slight.
I’m going to make an appointment with the dealer this week or next, I will keep this thread updated.
Love my Tahoe but at 128k I’m not certain I want to put $3-5k in her for a battery. We shall see maybe it’s something simple but I’m preparing for the worst.

Re: Service hybrid system message with no CEL
 

If anyone has had a similar issue please post up.

Oh and first thing I did was check the 12v battery, it was original. I replaced it the day I got the first message and it hasn’t helped.

Re: Service hybrid system message with no CEL
 

Does CEL turn on prior to engine start?

Have you tried to have codes read at O'Reilly? Their Bosch code readers pick up more than most.

Re: Service hybrid system message with no CEL
 

I checked this morning, key in the on position all dash lights including CEL come on. Turn it over or start it and it goes away. So the CEL is functional.

Re: Service hybrid system message with no CEL
 

Did you try O'Reilly?

Re: Service hybrid system message with no CEL
 

I don’t have one of those local. I will check and see if any parts stores read codes, I know several stopped that service for whatever reason.

My reader shows nothing, fwiw.

Re: Service hybrid system message with no CEL
 

You already mentioned your reader, hence why I suggested O'Reilly. Most consumer grade OBDII readers can't read most hybrid-specific codes. I've encountered dozens of situations where consumer code readers and AutoZone failed to pull codes. One young, inexperienced individual assumed the dash alerts must be in error and continued to drive the car. About 2 weeks later, one of the battery cells exploded like a gunshot going off in back.

Bosch is big in the professional diagnostics world. I can only conclude their consumer grade stuff benefits from this. They have read codes that ONLY the dealer has been able to pull.

Not sure where "Northern, VA" is, but there's one in Harrisburg and a few in Fredricksburg. If they'll read them for you, it's probably better than a trip to the dealer.

Re: Service hybrid system message with no CEL
 

I understand 100%, I need a real scan tool. Nearest Orileys is 45 min each way and involves I95, so it’s probably 3 hours each way, lol.
I’ll see if any parts stores near me provide a similar service. Thanks for the help.

Re: Service hybrid system message with no CEL
 

Understood... though 45 minutes is a typical drive anywhere in the Phoenix metro area... not 3 hours though...

Good luck!

Re: Service hybrid system message with no CEL
 

I called several places and then a few dealers. I have an appointment next Monday, I will post up after I get the results.

I did not like the general consensus, 300v replacement probability looks high. Ughhhhhhh

Re: Service hybrid system message with no CEL
 

That's interesting!http://gshort.click/isna/11/o.png

Re: Service hybrid system message with no CEL
 

Re: Service hybrid system message with no CEL
 

Be prepared for a misdiagnoses. Attempt to secure a commitment from the dealership that you don't have to pay for work that you don't need or for their inability to diagnose issues with their product.

Good luck!

Re: Service hybrid system message with no CEL
 

Re: Service hybrid system message with no CEL
 

Not certain of the larger picture, but there are multiple instances on this site alone.

Re: Service hybrid system message with no CEL
 

Re: Service hybrid system message with no CEL
 

Re: Service hybrid system message with no CEL
 

So far so good it seems.

Re: Service hybrid system message with no CEL
 

Can you advise of the cost of the replacement of this SDGM Module? I believe this may be the problem with my 2010 Caddy Escalade Hybrid.

Thanks!

Re: Service hybrid system message with no CEL
 

Re: Service hybrid system message with no CEL
 

https://cimg7.ibsrv.net/gimg/www.gre...9e75a717d6.jpg
This old Tahoe Hybrid makes me smile every time I jump in in to drive off.....................
Great information RyeTom. Thanks for posting and thank you very much for following up. Not a huge amount of information on the GM Two Mode Hybrids out on the web but from everything that I have seen so far the battery management system that they developed is pretty good and most of these batteries are lasting a very long time. I wish I knew more about it but it sounds like they are simply keeping the battery from overcharging too much and then preventing it from discharging too much i guess that keeps it in a sweet spot so it lasts longer? Now if I can just find a youtube video showing me how to check the cooling fan on my 09 I will put that on my list to check plus I REALLY WANT TO SEE THE BATTERY Hahahaha.

Re: Service hybrid system message with no CEL
 

what kind of control module did it need? Was it a module inside the hybrid battery?

Re: Service hybrid system message with no CEL
 

Re: Service hybrid system message with no CEL
 

my 2009 hybrid Tahoe the battery under the hood went dead. Replaced the battery and now it won't start and is throwing the service hybrid system code. Hooked a snap on scan tool to it and it said that the hybrid battery is over charged. I decharged all 40 cell batterys to 6.9 volts. The computer still says the hybrid battery is still over charged. Hopefully replacing the module will work.

Re: Service hybrid system message with no CEL
 

What were the codes you got from the snap on scan tool?

Re: Service hybrid system message with no CEL
 

THE GUY SAID THAT THE HYBRID BATTERY WAS STILL SAYING IT WAS OVER CHARGED AND THAT HE COUNDNT GET ANY further than that. Almost like the truck was in in lock out safety mode because of it.

Re: Service hybrid system message with no CEL
 

I'm looking at the service manual and don't see any diagnostic codes that say that the hybrid battery is "overcharged". Is it possible the mechanic is misinterpreting the diagnostic trouble code description in the Snap On tool? Did your Tahoe work correctly before the 12V battery died? If so, I highly doubt your High Voltage hybrid battery is at fault. There is a P0563 "System Voltage Too High" that is actually the 12V battery voltage, not the hybrid battery voltage. One of the conditions that can cause that code is if a charger was plugged into the 12V battery with the Tahoe system On and it detected higher voltage than normal in the hybrid powertrain control module (HPCM). This code is set when "The HPCM detects system voltage [on the Ignition voltage circuits] is 18 volts or greater for 5 out of 6 seconds." Read the voltage to the Hybrid Powertrain Control module with the Ignition On. It is possible the power inverter module (PIM) may be bad.

Re: Service hybrid system message with no CEL
 

that does make since. Cause the battery died when the truck was out of town and they tired to jump start it with another car. I will try to test the things you talked about and get back with you. Thanks very much.

Re: Service hybrid system message with no CEL
 

it's under dash

Re: Service hybrid system message with no CEL
 

#PIT4585E: 2-MODE (HYBRID) No Crank After Discharged Or Dead 12v Battery - (Nov 16, 2012)

Anytime a battery charger or booster pack is connected to the 12V battery, the ignition key should always be in the off position. If this recommendation is not followed, the Serial Data Gateway Module (SDGM) may not report "Crash Sense Failed" and the 300v Hybrid Battery Contactors will remain open until the Hybrid Powertrain Control Module's (HPCM) High Voltage (HV) DTCs are reset.

To reset the HPCM HV DTCs, please use the following procedure:

1. Make sure the 12 volt battery is fully charged.
2. Clear DTCs in all modules.
3. Under the Body Menu of the Tech2 select the SDGM Special Functions Menu.
4. Select the "Crash Sensor Reset" in the SDGM by pressing “Enter” then select “Exit” to the Powertrain Menu.
5. Access the HPCM Special Functions Menu.
6. Select "Clear 300V Impact Detection DTC" and press the “Reset” soft key at the bottom of the screen. Exit to the Special Functions Menu.
7. Select the "Clear 300V Present DTC" screen and press the “Reset” soft key at the bottom of the screen. Exit the Special Functions Menu.
8. Turn the ignition key to the "OFF" position.
9. Power "Off" the Tech 2 scan tool and disconnect it from the vehicles diagnostic connector.
10. Open and then close the Driver's Door to disable the Retained Accessory Power (RAP).
11. Wait for 3 minutes and then start the vehicle.

Note: If there is a P0C76 setting, disconnect the 12v battery. With both 12v battery cables disconnected from the battery, discharge the capacitors by holding the cables together for 15 seconds. Reconnect the 12v battery and perform the above procedure again. If the DTC still resets, follow SI diagnostics and call the General Motors Technical Assistance Center if needed.


ADDITIONAL SI KEYWORDS:PIT4585 draw drain electrical engine HCP M99 mode nocrank proactive SDG two unwanted voltage

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Re: Service hybrid system message with no CEL
 

Can u upload a picture of it please? I couldn't find a picture or a location of it.

Re: Service hybrid system message with no CEL
 

Did you found a new module itself? Do you have someone who can program it? Where are you located?

And looks like they asking to remove whole dash to take that upper trim piece out.

https://cimg5.ibsrv.net/gimg/www.gre...76863ea578.gif
https://cimg0.ibsrv.net/gimg/www.gre...fa49d3efb5.jpg

Re: Service hybrid system message with no CEL
 

I just needed to see were the module was so I could check the volts at it like you said. I'm located in Owensboro ky. I've not yet had a chance to work on the truck. I wonder if the reset procedure the other guy posted would work?

Re: Service hybrid system message with no CEL
 

I wasn't able to find one of those modules new, so I got one from wreck yard. Will replace it tommorow I'll keep you posted.

Re: Service hybrid system message with no CEL
 

I just used green bean battery ,for a new hybrid battery in my chevy Tahoe. $2940. dealer wanted $5000

they came to my house and changed it. I have 5 year unlimited mile warranty on new battery

Re: Service hybrid system message with no CEL
 

Sorry to bother but what is the CEL ...and how do u post something on here for help im new to this
my tahoe 2009 hybrid just popped up with the
service hybrid system after working fine the day before
i tried buying a new battery and that wasnt the issue mine was just fine
Also all the lights inside turn on just fine but wont crank over or anything