TCM Flash - NOW TRUCK WON'T START - HELP

[brossjd]

I have a 2005 LLY /5spd Alli. This is my first use of EFILive. I uploaded the TCM successfully. I changd the max shift defuel to from 89% to 50%. I flashed the 5spd Ali TCM back into the truck. Now it won't start.

The TCM flash said it was successfull. I don;t have any errors or tr0uble lights.

Can someone please help me get my truck running again!

Thanks.

[LReiff]

Flash the original tune file into the TCM and see if the problem goes away.

[brossjd]

I tried that right away. No luck.
I also took the battery cables off for a few minutes, No Luck.
I tried a Vats relink, no Luck.
I set the Vats to disable in the PCM, No Luck.

[LReiff]

Does the engine crank/turn over?
Did you change the Vin that's stored in the TCM?
Did you check the stored vin against your trucks vin?
To change the vin, open the scan tool, select the proper controller, then at the top of the page click on Bidirectional>Change Vin and enter the proper vin.

[brossjd]

Yes the engine cranks, it just won't fire.
I just checked th vin and it matches the truck as well as the PCM.

One wierd thing, Even though it was showing the correct vin, I tried to use scan tool to reset the vin as explained, but it failed with "Security Access Denied"?

[brossjd]

Thanks for the help so far!

[GMPX]

I can't think why the engine would not run after a TCM flash, can you read the ECM?

[brossjd]

Yep I backed up both before starting the whole process. I can read and write both without errors.

I can't think of any scan tool pids to watch to see why it won't start. It's got to be something with the Vat.

[brossjd]

I'm trying the whole Vat relearn timer thing now. 15 min key on for 3 cycles. I can't think of anything else to try?

[ChipsByAl]

Do you have any DTC's
AL

[brossjd]

Well the three 15 minutes cycles didn't work either. The truck still turns over, but won't start.

Any other ideas?

I'm afraid I'm looking like a tow truck to the dealer, who will for sure tell me the PCM and TCM are cooked.

[brossjd]

Yes I do have some DTCs but they were there before I started. I've been fighiting the Servic 4wd message for years.

I have:
-U0106 Lost communication with glow plug module (I think it was there before, but not sure)
-C0379 Front Axle System- Transfer Case shift control module I replaced the transfer case shift encoder motor years ago. The 4WD worksm but I still have this code.
-C0035 left front wheel speed circuit- Electronic brake control module (I changed th wheel bearing about a month ago and this cleared) not sure why it is showing up now.
-

[dansdieselp]

Have you done a Full reflash into the TCM?

[ChipsByAl]

What about the ECM. Have you tried flashing it back to stock? Does the security light stop flashing and remain off? Does the truck have any aftermarket remote start alarm system on it?
Al

[brossjd]

Yep I've tried a full reflash of both the TCM and PCM. Both went in successfuly.

The security light goes out and stays out. So I think the Vat is satidfied.

No I don't have an alaram or anything like that, but I do have an aftermarket Kenwood Radio.

I'm back at again this morning. But she's still not starting. I can't give up I have a 50mile drive to work in the morning.

[brossjd]

Update:

She's running again.

I just got her back from the dealer. They said the fuel system had lost prime. It's never done that before. I can only think a dump valve or something triggred during the TCM flash. Who knows?

All they did was prime the filter, and it fired right up. Of course everything is back to stock from all the precautionary reflashes, and I don't dare hook up the EFI Live ever again.

So I'm out a $215 tow truck bill, but the dealer didn't charge me anything. So if you ever need Diesel truck help in the Birmingham AL, area. Royal GMC seems to know thier stuff and are good to thier cusomers.

Thanks to everyone who took the time to help me!

[Meshanic]

Losing fuel prime isn't uncommon on a Duramax. Since the fuel system isn't pressurized before the CP3 pump any leak at all, most commonly by the fuel filter or housing, will allow air to get in and the fuel to run back towards the tank.

What I'm geetin at is you shouldn't be discouraged about using EFI Live. The coincidence that this happened for the first time right after you used EFI Live for the first time kinda really sucks! I might have had a similar reaction if it happened to me like that but truthfully EFI Live has gotten me out of a bind more often than I can recall.

By reading your posts it sounds like you just got more comfortable flashing and full flashing! Have fun with this! Just be ready to prime your system because it will more than likely happen again until you find where the air got in.:)

[killerbee]

...I don't dare hook up the EFI Live ever again.


This must be a bizarre coincidence. Update if you have another no-start, just can't think how flashing can create loss of prime.

[schwoch1]

I think it was just coincidence that it happened. I have flashed MANY duramax PCM's and TCM's and never had an issue. AS far as never hooking up EFI LIve again...... I don't understand what your logic is there????? SO what you are basically saying is, I just spent $700 or so dollars on a V2, but now I won't use it because my fuel filter lost prime after I flashed the TCM??? I am thinking the truck probably would not of started even if you did not flash the TCM with EFI Live, so who would you of blamed then?????????
Just my $.02!!!
Mike

[brossjd]

Thanks to all the replies.

The reason I blame the EFI live is this.

Just before the TCM update flash, the truck started up fine after sitting for days to move it on the driveway. After the flash it would not start. Like I said before, the truck has never lost prime in 6 years, and has not lost prime again since the flash. Even after sitting for three days.

If I had a bad enough leak to cause the truck to loose prime in only the time it takes to download the flash, I would surely have had this problem before, or would have seen it since.

Looking back at what all happened; I think maybe I had a VATS problem, or something, after the first TCM update flash. After trying to the start truck several times, I may have lost the fuel in the filter. At some point, my reflashes, or time based VATS relink fixed the electrical problem, but because I had no fuel in the filter she just wouldn't start.

After even more reflection maybe the problem was the Diablo locking the ECU. When I loaded the first TCM flash, the ECU still had my Diablo tune loaded in. At some point, I used the Diablo to return the ECU to stock. Maybe this unlocked something, and let the truck electrically try to start, but I still had the drained fuel filter.

I hold nothing against the EFI live software. It's just that I can't kill my daily driver anymore. The software / GM ECU flash process is just too flakey. I actually bought the software to load up a new E40 ECU for my C6 Corvette. My Vetts ECU died while out driving around. It showed a ram check sum error and would shut the car off every three minutes. The software worked great for that task, and like others said, saved me money in the long run. So I have experience flashing my Vett several times, and never had any issues. This was the first time hooking it up to my LLY.

I am an industrial automation engineer for a living. I write and modify process control software every day. If I had a machine working for six years without a glitch, and then uploaded even the smallest change, and then my equipment stopped working; the first place I would look is my software, not the hydraulic or pneumatic systems etc.

The clincher...... I have since found 2 other people with LLY trucks who lost prime after flashing their trucks as well. They tell me to just go ahead and flash away, just pump the primer after each flash.

Let's face it; just because yall haven't heard of it before, I know in my mind, it's yet another side affect of this process.

Thanks again to everyone who tried to help me out.

[cumminsDK]

You should maybe study the fuel system on your truck not possible for a flash to cause fuel drain back that would be like your software at work causing a hydraulic fitting to loosen up

[Meshanic]

You can rule out the VATS speculation. In theft mode the truck will fire and die. The fuel delivery system is mechanical aside from the actual injectors. Even the pressure relief is mechanical. Elecronically it can only command the injectors not to open and your fuel pressure is normal when in theft mode.

I see this all the time and have never thought much of it. One of my LBZs did this yesterday. Prime and go back to work.

[killerbee]

If you spent a bunch of time cranking over with a VATS (or other) dead issue, then perhaps that is what drained your lines. Just a thought.

I have flashed thousands of LLY truck, and never had this happen.

[dansdieselp]

Sounds like you need a lift pump bud. Losing prime is a mechanical problem, not electrical. You have an air leak somewhere in the system. It will happen again, but next time you might not be at home when it does it.