FYI - Plugged in Block Heater can trip the Check Engine Light
We've had that annoying little Check Engine light come on a few times last year during winter, and now once again this year.
We brought it by the stealership and apparently, if you happen to start the car while your car is still plugged in, it can upset the Jeep's computer. It's been a known problem with the '08s. They ended up flashing the computer to update the firmware.
I admit, I normally start the car, and then go unplug it. Sometimes I do it the other way around. I've never known it to be an issue before. Although now that the computer is flashed, it's supposed to be alright now.
Just thought I would share the experience to fellow MK owners - especially those with the block heater.