I had my turbo brake activated through EFI back in July and it's been working just fine. A couple of days ago it was about 18 degrees out and I noticed it wasn't working on my way to work. On my way home that same day it had warmed up to about 45 degrees and the turbo brake was working fine again. This morning it's about 32 degrees and it's not working again. It doesn't make sense to me but would the cold have any adverse effect on the TB working or would it be something else. I've done nothing to the truck since I installed the tunes. Any ideas?

do you have the ability to monitor the Turbo Vane position? Could be it is sticking when the OAT is low?

I don't have any way to monitor it. I don't know what OAT is? Outside Temperature? May be sticking. But I park in my garage all the time and the temperature never gets below 42 even when it's below zero outside. On the days in question thus far it's been at least 52 degrees in my garage when I start it up in the morning. Maybe the cold air hitting it after I get going down the road is making it stick? I have no idea.

OAT = Outside Air Temperature, easier to type than Ambient air temperature.

It would be interesting to know ur vane position when this happens. When the TB activates the vanes go to 100%, then fall off as the truck slows, then up to 100% again when the xmsn drops a gear.

I agree. I'd like to know the vane position also but I can't foot the 400 or so dollars for an Edge insight. Sorry to be so stupid but now I don't know xmsn?

Drove it home bout an hour ago...Temp outside is 50 degrees and the TB braked worked again. Maybe coincidence... maybe not.... but I'd like to know if it is the temp and why. Kinda frustrating.

OH! I get it....xmsn = Transmission. I'm an idiot. Mines a manual by the way.

Manual xmsn, no TH mode, so the TB is normally active all the time?

If so I dont' think I would like that. On a previous truck I activated the TB through grounding a pin in the C2 connector for the ECM. When I first tested it, I did not have a switch on the ground. The TB was VERY effective. I could not want to get back and install the switch to turn it off when not towing my 5er.

You can often find a CTS or CS used on eBay for less than a CTS2 new, often for less than $200.

The guy who programmed it has it turning off at 1400 RPM's so it's kinda not on all the time and when you drop below 1600 or so RPM's you can't really tell it's on anyway. I also have 2 of my tunes without the TB activated if needed.
I'll check out eBay and see what I can find.

Here is one that will work, it is an Evolution which is an Insight with non-delete tunes but it will work fine for $200

https://www.ebay.com/itm/Edge-evolut...sAAOSwPkhdwJJQ

It says... "Edge evolution cs2 gas Power Programmer Chevrolet and GMC trucks 2007 and up."
Mine is a 2006 diesel. Would it still work?