Hi i have a 2002 gmc sierra diesel and i was driving down the road and the security light came on and the truck put it into 4low and wouldn't come out.I drove it home in 4 low and started looking into it and still can't figure it out. I hooked up my scan tool to it and I got codes PO500, PO700, PO836, PO2106 one was for vehicle speed sensor and another was for transmission fault and the other two it didn't say what it was for. When i push the button to put it in 2 wheel drive nothing happens. It dosen't even try to do it. Let me know what you guys think. It seems like the truck is in anti theft mode but it still lets me start the truck. I appreciate the help
Josh

 

not sure with all those codes....is this an electronic transfer case?

 

yes it is. i just need to find out what these codes mean than i am sure i can figure it out. I am going to the dealer tomorrow to ask them
codes po2106 and po836
thanks

 

p02106 is not a code..too many characters...


DTC P0836
Circuit Description
The 4WD low signal is used to notify the transmission control module(TCM) that the vehicle is in 4WD low range.
DTCP0836 is a type B DTC.

 

I assume this is a Diesel? u2106 is a communications code

 

My buddy couldn't get his '01 out of 4Low when we were on a lke ice fishing. Truck would try to engage and then click out to neutral or 4 low and wouldn't get into 2 or 4 hi until he let it sit and restarted after 20 minutes or so. Fell under warranty work...not sure what they did.