Hello all, I am in need of assistance to work myself out of situation where I am pretty much stranded. The truck is in the eastern sierras 300 miles from the nearest dealer north (Reno NV) or South (Palmdale CA). Snowstorms have been constant since before christmas with 441 inches so far in the area and still coming (just in the last 4 weeks). See photo of the truck this is after 3 major dig outs last week alone. I have to get this moving...

Leading up to this the HV battery was dying. The engine at 150K miles had a crashed lifter, I opted to put a Jasper rebuild in it, and it now has approximately 40K miles on it. So at 192K miles and after some research I decided to purchase some of EnnoCar newest "Steel Prismatic" cells to rebuild my battery. I liked these cells because of the higher discharge nameplate of 45C. That I believe should show up as higher capacity and longer life in the long run. I see lots of opinions here now on some of this Chinese cell product, and I will be interested to see how these hold up capacity wise now that I know how to test everything on them. ...videos for another day if I can ever get this thing going.

So... Battery is dying, I often get end of discharge cycle codes for divergence, and I get the normal thump and bump going into autostart that everyone reports. Truck runs fine with an occasional hybrid fault that clears on an ignition cycle. ...I'll get to that battery rebuild soon, I will, I promise, I will. The check engine light sometimes will disappear for days and then return... I'll get to it I will!

Now to today. We are out skiing, it is a crazy snowy and windy day, girls are all cold and they hit the car first. They jump in the car, start it, and run anything and everything that can put out heat. This truck is super nice because the seat heaters and the blown heat come on right away in these conditions. A bit later as I am taking my ski boots off (1/2 hour or more later) the truck drops into Autostop while I am sitting on the bumper and everything appears normal, a few minutes later I get in the truck and there is a "Hybrid System Fault". I turn the key off and then back on to clear it and... No crank. literally no, crank not even 30 seconds later. The 12V seems really strong but its always hard to tell with no external load measurements. I try to jump it, no change. I then fire up the code scanner and clear all the codes, no change. I then try to jump it again giving it some time to charge, all seems the same relative to 12V charging, seems strong, again no crank.

Hmmm... I finally get a tow truck to get me off the mountain around 1 am, before the monster plows bury it until spring. Whew.... They don't want to tow it to a mechanic because everyone wants their lots free for snow plowing. So I tow it to a friends driveway where there is very limited parking to the fact there is NO WHERE left in town to put any snow... So I am 500 miles from home taking up space in his driveway and a bed. I gotta get this thing moving, but now I am really beyond my knowledge of how this thing starts. Please, any help or ideas appreciated. I can get mail or a UPS shipment here, and I might be able to thumb a ride back to LA but screwing around with this much more is really starting to cost me. Story continues...

I begin reading and trying to figure out whats wrong... Knowing the HV battery was a potential issue, I decide after a couple of days to pack the wife and kids and the HV battery into a rental car and zip it back to LA (she needs to get back to work, thankfully I can work remote some). Once there I take a day rebuild the battery (see pic with new EnnoCar cells) and head back on up. ...at $150 bucks/day I can't hold on to this rental too long. When I disassemble the battery all cells are north of 8.1V, so I am think hmmm... this shouldn't have been the problem. The new cells are right above nameplate at 7.3 ish volts. You will see in the diag data that they show 15.7V per block. I decide its time to just proceed with the rebuilt battery and continue course.

After racing it 7 hrs north and finding a couple poor souls to help me lift it in, I re-install the battery, ...and NO CHANGE! ...same thing turn the ignition all the needles dive like its going to start and then nothing. Maybe a very quiet click somewhere under the hood. Thats it.

I rescan everything and there are no codes that should prevent starting, just some left over from disconnecting everything (i.e. left and right door window cals, an EBCM fault, and SRS fault thats been there for 2 years). UGH!

So I continue reading much of what you guys have posted. My scanner is an Autel AP200, I really like this little bluetooth guy, but it can't do more than read and reset codes. ...but at least it can read data from all the modules!

...so there are 6 mechanics within 100 miles all of them use Snap-On scanners, and all of them to a tune say they have no idea how to work on a hybrid and they are pretty sure their Snap-On scanners cannot send the GM special functions. Autel tech support was nice enough to call me back and tell me there was no hope to get my Autel AP200 to send the necessary commands even with a macro or something. Snap On never bothered to call or write back.

I suspect one of the "precharge" or "300V isolation" codes are blocking the start, but I don't know how to tell. I have attached all the diag data I can get from the AP200 here. I have fully tested and charged the 12V battery. ...and now with the tools I have I am at wits end.

It will be $1000 tow to get it to someone who might be half knowledgable 300 miles away and have a GM Tech 2. So my best options are (1) buy a tech 2 clone with expedited shipping, (2) buy another bidirectional that supposedly has the special GM function commands, or rent a pick up and a car hauler and get it on to a trailer myself and get it to someone more knowledgable in LA or Reno.

I am hoping some can look at the data I have and tell me what is inhibiting the start. Also in looking at scanners it seems a shame to spend a bunch of money on an EOL GM tech 2. Does anyone have any experience/luck with any of the other off brand scanners that seem to have a lot of capability (at least by their brochures).

Here are 3 I thought interesting:

(1) Foxwell GM Full Scanner

https://www.foxwelldiag.com/products...hoCmroQAvD_BwE

(2) 2023 Elite LAUNCH X431 GM Full System Bi-Directional Scan Tool


(3) Xtool D7

https://www.xtooltech.com/

If you look on the xtool site the thing has pages and pages of codes and functions it can do and looks to have everything I've seen referenced as things I need to be able to do, and it looks like I could use it on other cars like my BMW etc. ...including those listed in "Doc ID 1983521" looks to be the next steps I need to take in Diag?

In short, from what I can tell are the HV contactors are open and I somehow at a minimum need to get those to close to have a chance. Agree?

...any help or thoughts would be VERY much appreciated.

 

did you try remote start?
make sure to put it in M4 to keep it from going into Autostop once you get it going

 

I did try remote start. It made the same subtle click as it makes with the key. I tried it with hood open, hood closed, etc.

This video shows what it looks like:


The crash sensors are not set, but if you look at the diagnostic data, it does have the 300V AC isolation "indeterminate" he shows there on the tech 2. Not sure if that is a reading or...

Thats why I was thinking I need a bi-directional scanner with the right commands. Seems the only "for sure" source of clearing this is the GM tool. It would be great if someone knows of another, hopefully cheaper, option!

Thanks for noodling on this!

 

Did you lock the safety plug into place? It's a three step process. Need to do the steps in reverse of those shown (circled) with the final step sliding the handle down to lock it in place (indicated by arrow):

 

i would inspect the HV cable it might have damage.. it's under the chassis be sure to disconnect the HV disconnect before hand
a rock or road debris, may have damaged one of the 6 cables and it's grounding out to the internal ground cable or chassis ground

11.63volts at the battery may cause an issue as it's fully discharged and requires 300~400 amps on startup, should be 12.2 or higher, 12.9-13.0v is fully charged

 

I did confirm the disconnect is both in and down, set it and reset it a couple of times with no change. I can check the cables under the chassis when I get a chance, but I am thinking the high voltage isn't being applied. Along the lines of Kieth's question... I suppose that could be an open on a cable. The contactors being open (ni the battery as I understand it), I thought I read somewhere you can command them with the scanner? Do either of you have any familiarity with that? Without them closed as I understand the system, HV can't leave the Hybrid battery, is that right?

It seems there are several different safeties which will shut down the HV, I was thinking if you could clear them and get the contactors closed and somehow verify that it would be the first step to know that HV was going to the inverter. It takes so long to run the full diagnostic report, i.e. 15-20 min, and then longer to grab the live diagnostic data that shows some status rather than just codes and that causes the 12V battery keeps coming down. I have been continually charging it and load testing it. It does deliver full load amps on the load tester without dipping below the green zone.

Are the autostart inhibits potentially the issue. Or would all those be bypassed by the remote start? I can't find anywhere that shows the conditions/logic that has to be in place to support a start.

Thanks!

 

check the transmission connection pins as well 08-07-30-021G 1..21 (nhtsa.gov)

don't forget the fuses if you have not checked them as well including the 60Amp (for the transmission pump )fuse in the Aux fuse box..

Does the Aux transmission pump turn on when you key on? i would also check the connectors on the AUX pump they get dirty and cause a problem...

it would be great if you had a current meter to check the aux pump wires if the pump isn't working it's not going to start..

have you tried starting in Neutral gear? (make sure to have the e-brake set and/or blocks so you don't roll away)

 

I looked at the pdf but I don't see the obd2 codes? do you have a list of those that currently set?

as I understand it there's 3 contactors in the battery. one for + on for. - and one for the resistor that closes to avoid big voltage arc when the others close. it also checks for voltage to ground to make sure those contactors are not stuck closed. lots of safety checks go on during first key on to make sure nothing has failed that will shock someone with 300v DC. trouble codes should be able to point you in the correct direction.

what fictions are you looking for in a scanner?
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The only current codes from the summary report are:

B320A-4B (Driver Door Switch - window cal not learned) - I believe from disconnecting the 12V
C0561-71 (EBCM data invalid serial data) - I think this one was on during my last smog, appears to be some sort of intermittent caused by wheel slippage (i.e. lots of snow!)
C0558-4A (Electronic Suspension disabled) - Been there since I replaced the shocks several years ago.
B320A-4B (Passenger Door Switch) - same as above but for passenger door. - surprising that its the exact same code twice. But when I go into the switch there are several subcategories and these are a called out separately.
B0083-DF (Supplemental inflatable restraint, front end sensor 1, erratic) - Also has been on over a year. A wiring issue I can't track down on the Left side front impact sensor. Has never caused any problem other then turning on the airbag light. A pain...

I don't see any of these as something that would inhibit start. Am I wrong?

The resets I want to do are the ones shown in the you tube video in the previous post as well as be able to command the contactors I think. On the GM Tech 2 they are shown as "GM Special Functions". Apparently these kinds of commands are need to calibrate actuators, or command switches etc. When I read about people say its a bi-directional scanner. I have no history with this level of tool, thats why I was asking what is a good one that I can use for multiple applications. The Xtool D7 does look interesting in that respect, but whatever I buy I have to make sure gets me out of the preverbial ditch I am in...

I do have a current meter, any more specifics on how I check the transmission stuff. I also did try to start it in neutral (with just the brake on). I do have the underline the symbols for Park, Drive, Etc. I read somewhere that indicates proper transmission communication?

Thanks again all!

-Tom

 

huh, I just watched the first seconds of the video when key didn't do anything. I should watch the rest.

that's weird thou you don't have a code but it did say service hybrid system on the display? these things throw codes like crazy I'm surprised there's nothing more.


only guess I have and you checked it already is that impact sensor triggered the crash code. I've seen posts about that set from a big pot hole. but you said you don't see that set.

yeah, I got nothing man. honestly if it was me and the transfer case would go into the tow setting where a tow dolly wouldn't hurt anything, I'd rent one from uhaul, borrow a truck and just get it home at this point. only say dolly before it's a ***** to get it on a trailer without a winch.
in the owners manual it shows you how to set it up for flat tow behind a rv if you have a model that will allow that.
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