Help: Truck stays running after the key comes out

[calereeves]

2008 LMM Crew Cab Dually, LTZ, has remote start. A few months back I noticed sometimes (not every time) I would get out of the truck, it would stay running for about a minute, maybe less after I take the key out. It shuts down on its own, but it acts like I've remote started it and the HVAC comes on, but you can't adjust anything, and the radio is off.

Any ideas on what's causing this? Talked to my wife today as she was stepping out of the truck and said it was doing it again. Turned off after about 20 seconds.

 

[calabria69]

Turbo timer??

 

[Bryce418]

I had a truck come through our shop (also an LMM 07 if I recall correct) had a consistent 15 second run on time after the key was shut off. After chasing down what circuit was staying powered, I started disconnecting components and the tcm ended up being the cause.

 

[calereeves]

So what did you do to correct it? Was it a faulty TCM? Sounds like I may need to take it in for warranty work?

 

[Bryce418]

Yup replacement tcm fixed it. Don't truly know what happened but it was backfeeding keeping the run crank relay energized. It was a fun one to figure out for sure.

 

[calereeves]

How much did the TCM run you? Or were you able to swing it under warranty?