08 Tahoe Hybrid no start/ no crank after AFM valve replacement

[Rocket Man]

I just checked the Tech2 owners map and OR VietVet apparently doesn’t own a Tech2. I’m the only one in Oregon that I see. There’s a PDF that’s kept updated, click on it to see the list.

Tech 2 Owners Map

There are quite a few members that have a Tech 2 and there are always people who wish they had one to use so I thought I would post this thread to try and help each other out. If you own a Tech 2 and would be willing to help out another forum member that might be local to you then post up your...

www.tahoeyukonforum.com

 

[j91z28d1]

looking at your post, my first thought was did you click the extra little tab on the hybrid plug? it's simple but very common to miss it. you put the plug in and there's a extra tab you gotta click. there's a YouTube video if need be. but you'll. probably known if you did it.


I don't believe those are your hybrid cell voltages. there's 20 of them. alone with Temps that are good to monitor. they will tell you a lot about hybrid battery life. just buy a 300$ tech 2 if you own this truck for any amount of time. it's worth it, use the china link, I have it and it's priceless for trouble shooting. you can't even follow a trouble shooting tree without one. my truck has 30 modules in it to read. most scanners read one. my 3k work scanner reads about 10. the china tech 2 reads them all, with live data.

in the mean time, and for daily monitor I like using the torque app. if you have an android and 30$. you can add a bunch of pids for the battery cell voltages, Temps, current into and out of the pack while driving. fan speeds. stuff like that. you can't read the battery fault codes with it thou. well you probably can but I don't know how, the tq app message board is full of people smarter than me lol.

these trucks are very touchy about starting, anything out of sequence with the hybrid system will keep them form cranking, and it checks everything every time it starts. so yeah, gotta get some battery data, but especially the fault of code that prevents it from starting and go from there. in the mean time double check everything you removed. and charge the 12v battery out of the truck. like that plastic cover over the hybrid box under the hood. there a jumper in there that will keep it from starting it not installed. if the main orange plug is correct. anything hybrid related has a safety built in, so nothing is energized unless it's perfect.


how many miles and what year is your hybrid pack? how long was it apart since it last ran? if you're over 80k and 8 years, it's probably on its last leg. there's a section over on a electric car board, (mostly prius) that if you data log the battery under load using tq app, like max ac with window down and full accessories on. they will graph out your pack voltages and give you an idea how's its doing. but 99% of the time the center cells of the pack is damaged. it's made by the same company that built the prius packs, but horribly over used by the gm software and under cooled. so the packs don't make the 200k a prius does. normally by 140k yours struggling to drive the thing safely.

 

[j91z28d1]

A Tech-2 is not expensive compared to what towing this to a shop will cost. It'll be a bargain.

I wonder if there are internal BCM codes related to the "Service Hybrid System" message. There may also be Failure Records to view on this as well.

Where do you live? We have a Tech-2 owner's thread where you can see if someone lives near you.

Your batteries all appear near dead. The under hood battery ought to be removed or placed on a trickle charger.

@RebelBelle

I didn't know that those 6.0 motors used the cathedral heads. Painting the VLOM looks cool. Is it new? It is SOP to replace the VLOM and lifter trays whenever the AFM system is repaired.

yeah the 6.0 has the cathedral port heads, I've always heard they make more mid range than a rec port on the 6.2's, so kinda makes sense. that an they have a higher compression ratio, to help off set the late intake valve closing cam. I forget the name of that, but it's also gives up off idle tq for mid range efficiency. the electric motors help cover for the lack off the line power for the extra mpg from the late intake closing setup. that and the tranny is veriable ratio is a weird way, it will let the engine flash into its power band quicker too.

 

[kenny-or]

RocketMan: I totally understand not letting your tools go. I have learned that lesson as well but figured there was no harm in asking even is the chances were slim. I actually thought the scanner was significantly more expensive then $300. I had read on some other sites that the cheap ones were not the true scanner and that they actually cost around 2k. I was confused by this as I couldn't locate what they claimed I needed which is why I was asking. My current scanner cost me more then the tech2. Granted I don't have the extra cash to buy one this minute but I will soon hopefully. Then y'all can add me as the guy in Eugene with one lol.

j91z28d1: Thanks for your response and suggestions. I can only imagine your talking about the retaining clip that locks the plug into place? I'm not sure what other "tab" you would be referring to. My Tahoe has 265k miles on it but I have only put the last 30k on it. The vehicle was owned by the government prior to and had an extensive set of maintenance records. I have an Iphone but may get an android just to get the torque app. I'd love to data map the battery loads and so on. I think I read this vehicle has 15 batteries that make up the battery pack. Each battery cost about $50-60 to replace so if I find that some are bad I'll replace the dead cells. The car was apart for about 4 days while I replaced the valves. Outside of the valve compressing about 2 weeks ago the motor and the electric mode have been working perfect. I just cant imagine that the pack would have gone bad after 4 days of not being used when it has worked fine up to now. I do have it on a trickle charger now. Hopefully it can get it charged up and start. The cathedral heads are a pro/con when it comes to replacing the valves haha.

 

[kenny-or]

I'd still love to see a couple links to what you guys would suggest I purchase scanner wise if you wouldn't mind

 

[j91z28d1]

with that milage, it's forsure been replaced. I do think a few days of being apart is fine. I think you're missing something when putting it back together.

I've rebuilt my battery, not using oem stuff, but your battery as 40 cells in it and a voltage monitor per 2 cells, so it will read as 20 modules. has 6 temp sensor, one in the intake port, one on the exhaust and 4 on the batteries themselves. when your battery goes, the truck will start to jerk as it starts the engine while moving the truck coming out of auto stop. it will be worse on hot days when max ac is on.

I'm a bit confused. you replaced the afm lifters with new afm lifters but also replaced the valves in the heads? I understand that's a lot of mileage, and you can have some valve guide wear, but I've not heard much of replacing the valves themselves?

I'll look for the links in a few mins, there's a app I believe works in iPhone, but it's not customizable to add pids, and I can't test it, but I believe it might tell you cell voltage as well. you can try it with the same 30$ obd2 blue tooth scanner.


what scanner do you currently have? will it show anything under a different section? if it's more than 300$ I'm a bit surprised it doesn't do anything more than the ecm.

 

[j91z28d1]

scanner..

this is what most people get I have it and another one that works but this the most link I got mine from.

for Android Phones ONLY - Wireless Bluetooth Diagnostic OBD2 Scanner Car Code Reader and Scan Tool for All 1996 & Newer Vehicles ELM327 Compatible OBDII https://a.co/d/7BEKQYJ


this is what the app looks like on my end that might be in the apple store, hopefully you have the same one on the IPhone side. or someone that has a cheap old android based anything you can borrow.

 

[j91z28d1]

this is the latch I was talking about. o
you. probably did it right, but just incase

here's a link to the tech 2 I bought, i got it off this site. in the long tech 2 thread.

Cheap GM Tech2/ Saab Tech2 Diagnostic Scanner Full Package

GM TECH2 Scanner Full package comes with free TIS2000 Software, you can choose one kind of software for GM, SAAB, OPEL, SUZUKI, ISUZU, and Holden.

www.chinacardiags.com

it will take like 2 weeks to ship, it comes straight from China DHL.

I'll attach a pic of what I monitor for hybrid battery voltage using tq app and a pick of inside the hybrid pack. I don't really think a dead pack is your issue thou.

 

[Rocket Man]

As far as the Tech2, the Chinese clones are what most of us are using. The company that makes them is the same company that used to make them for GM from what I understand. The link above is where I bought mine. It does take some time to get it. I heard of others finding US sellers but last I checked on eBay there weren’t however you might get lucky. You just have to make sure it has the latest version number. Chinacardiags is the safest way imo.

 

[kenny-or]

with that milage, it's forsure been replaced. I do think a few days of being apart is fine. I think you're missing something when putting it back together.

I've rebuilt my battery, not using oem stuff, but your battery as 40 cells in it and a voltage monitor per 2 cells, so it will read as 20 modules. has 6 temp sensor, one in the intake port, one on the exhaust and 4 on the batteries themselves. when your battery goes, the truck will start to jerk as it starts the engine while moving the truck coming out of auto stop. it will be worse on hot days when max ac is on.

I'm a bit confused. you replaced the afm lifters with new afm lifters but also replaced the valves in the heads? I understand that's a lot of mileage, and you can have some valve guide wear, but I've not heard much of replacing the valves themselves?

I'll look for the links in a few mins, there's a app I believe works in iPhone, but it's not customizable to add pids, and I can't test it, but I believe it might tell you cell voltage as well. you can try it with the same 30$ obd2 blue tooth scanner.


what scanner do you currently have? will it show anything under a different section? if it's more than 300$ I'm a bit surprised it doesn't do anything more than the ecm.

j9: Great info! Sorry for the confusion, I replaced all of the lifters not valves, I misstated. My current scanner is a Actron cp9690. Oh, in regards to the latch, I did get that secured properly but I can see how people would over look that.
I do feel like I am missing something in the reassembly but I have gone over it 100 times and can not find anything... That's what brought me to the forums to post for the first time.
My daughter has an android so I will just borrow her phone to play around with the apps.


RocketMan: I'll take a look to them when I have some cash for that. Hopefully it will not take me to long.