09 G8, read VCM and now no stability

Just read the VCM in my new 09 G8 GT, and now the stability is stuck on off. Also, there was a SES light for loss of communication with the TCM. Cleared that. Anybody else see this? Nothing was written.

Curious, which version are you using? The latest is 2.22.3152.18236 (at least as of this past Monday).

Also, have you been able to get your stability control back? If not, might I suggest removing the negative battery terminal for a few minutes, and then seeing if that works.

It is the latest version. Just updated it today. Going to try the battery trick later. Just thought it was odd. I've been tuning since the LS1 Edit days, and as the vehicles get newer, they just seem to get more and more quirky.

Pull the TCM fuse to reset it, I've seen this happen on a few G8's & some trucks.

Happened to me. Went back to normal after about an hour.

Mine did it to. Drove it a couple of blocks and then restarted and it was back to normal.

Mine just did it too. Scared the cr*p out of me. Came in here and was very relieved to find this thread. I drove around the block and started and stopped it a few times but I only gave it a few minutes. I will try again in an hour. It also would not let me shift into sport mode and the gear display in the DIC constantly said P (for Park) no matter what gear I was in. Hope that clears with the rest of it.

Any idea why this is happening? Will it take a write calibration OK?


Also, something else strange. The Speed on the Guage display in the scanner went right to 158 MPH (while I sat in my garage) and stayed there. I didn't play with it anymore after the other problem. Any ideas why that would happen?

Loss of ESP also happens in the VE Commodore which the G8 is based on. I think some of the modules lose communication with each other during a read/write and then set errors. They reset themselves after a short time.

One way around it is to do all your reads/writes with the key in the accessories position instead of the run position. The ECM & TCM will still communicate with your laptop but it doesn't generate any errors on the dash.

Great, I will give it a try.

I went back out and it was fine. Thanks for the input.

Finally, on a side note, check this out.

http://www.hptuners.com/forum/showth...321#post141321

Mine did it as soon as I connected to the VCM. It killed traction control and gave me ABS and some other warning. I let it do its thing (was downloading the stock tune).

After it finished, it "recycled" the vcm and the errors went away except for the "check engine!" light and the "traction control" error. I turned the car electrical off, then back on. Once it was done yelling at me about the errors, I checked the DTC's and it showed that there was a temporary break in connection on the TCM to the PCM/BCM/VCM/whateverCM. Once I cleared the errors, everything went back to normal.

Ya, just do a case relearn, and you're good to go.

Since it looks like me and you are the only g8 owners here...wanna swap files??

This also happens with a 2010 Camaro SS auto in case anybody else comes in with the same problem. I also had a bizzaro Service Airbag notification pop-up. Doing a battery pull clears the problem though. All good now. :)

all modules on the communciations bus lose communications to the ECM when you read/write it. Some recover gracefully, some not so...

Not to grave dig, but to add to the sticky for anyone who comes across this in the future... I noticed that this will happen if you connect the OBD II cable *AFTER* putting the key into the "On" position. Connecting the cable BEFORE turning the key to "On" doesn't result in this behavior (at least not that I've been able to find).

As noted, the "Acc" position avoids this, as well as strange behavior from various modules when doing writes in the "On" position.