This morning my 2012 Lariat 5.0 with 61K miles started fine despite the -9 air temp. (I had used the engine block heater - my timer allows it to run about 2 hours.)

As I slowly backed out of my driveway (in 4x2 mode), suddenly it started running a little rough, but not too bad. I then noticed the wrench icon in the dash. I shifted to Park, shut the engine off, started it back up, and the wrench icon was gone. I drove it to work (about 7 miles). It ran and shifted fine.

My understanding from the owner's manual, is that the wrench icon is related to a 4x4 system fault. But I've also read comments in this forum that the icon is related to the transmission. (Note: I've put on a few miles this winter in 4-High and 4-Auto, as road conditions warranted.)

I've owned this truck for about 2 years/20K miles and have never seen this before.

Should I do anything ? Write it off as a fluke ? Wait until/if it happens again ?

 

That does make a guy wonder though. If the light was on solid, I'd be more worried about it, but I also don't see why it would come on, then go out. I remember seeing that being something like a locking hub assembly if I remember right.

 

From page 14 of your owner's guide:





If you didn't get a 4x4 message, the problem had to do with your electronic throttle system. Best guess is it didn't like the cold weather, and the restart was all it needed.

 

I had been referring to Page 321 of my owner's manual, which is more focused on the 4x4 operation. I dont recall seeing the 'CHECK 4X4' message, but it might have been there.


Thanks for sharing p 14, which shows the issue can be more than just the 4x4 system.

I'll be watching this for awhile, but hopefully this was just a fluke, due to the cold weather, though this truck has experienced colder temps in the past without the happening.