I've been having the known issue with the "Sevice 4wd" prompt on my dash for a week or so. Researched it and found the common issue of the selector switch going/gone bad. So i ordered one. But in the meantime, second occasion happened this morning, after starting the truck and the prompt on the dash i notice that the switch is lit up in the 4wd lo position and the truck feels like it's in 4wd. Sluggish, won't kick down, etc. First time it happened, I was coming home on a highway and it quit acting sluggish and feeling like it was 4wd, but after several attempts at flooring it to get it to kick down. Ran fine afterwards. Then it does the same thing this morning on a short drive to work. My question is could the switch still be the issue causing this or something more? I'm still wating for the switch to arrive and will try that first, but wondered if anyone else encountered the same thing.

 

Probably not the switch. More likely an encoder motor or TCCM issue. Some TCCM concerns can be corrected by a reflash by the dealer. Might give them a call & ask them to look for bulletins that apply.

 

i'm gonna try the switch first, then if it's still doing it i'll check into the TCCM or encoder.

 

Cool, let us know how it turns out.

 

+1 culprit is most likely Encoder Motor Sensor because you have a 2006 which is in the range of years known to have this problem frequently. (I replaced on a 2006 model). It's a hundred dollar driveway fix if you just change the sensor.

The switch was a frequent problem through 2003 models. (I replaced on a 2000 model).

Good Luck.

 

Yea, I replaced the switch on my 99, and have heard of many others having the same problem. I've also read of many encoder motor problems, but didn't realize that the switch/motor problems were associated with different years.

 

Well, the switch was changed out with a used 2006 lower mileage switch and still the same issue. So the truck is going to my buddy's shop wednesday to read codes and diagnose. Then whatever it needs i'll do myself it possible. If it's the encoder motor sensor, how hard is that to replace at home?

 

Truck is fixed now. It was the switch...both my original and the used replacement I swapped with. My buddy diagnosed and come down to a new switch with resetting code for service 4wd light. Lesson learned - buy NEW dealer electronics. Much happier now.