2003 Chevy 2500HD "Service 4WD" Indicator

[Russell]

Hey guys!

My father and myself went out tonight to move a car for a buddy from his place to the tranny shop using my father's `03 Chevy 2500HD Duramax with an Allison automatic 6 speed, and some electric shift transfercase.

We got to his place, and shut off the truck, loaded up the car on the dolley. When we fired the truck back up, it gave an error message of "Service 4WD", and disabled the transfercase switch...

Does anyone have any ideas what might be the cause? It came completely out of the blue, and we hadn't touched the transfercase at all... The truck still runs and drives just fine in 2wd, and isn't making any unusual noises...

Thanks for any help!

Russ

 

[73k5blazer]

it gave an error message of "Service 4WD", and disabled the transfercase

I don't have an answer for you,beside check the shift solenoid. That's a total guess though.
But this,the quote, is extremely disturbing.

 

[moneypit]

encoder motor is bad.

 

[5280k5]

You're best bet is to get it scanned and see what failure code is stored in the transfer case module. Right now there are several common problems with the t/case control module, encoder motor position sensor, and software in general with the electronic 4wd in that truck. Depending on what code is there: c0550 is t/case control module failure & would need replaced and reprogrammed with new software, c0300 or c0305 may just require a new software download, c0374 may relate to a speed sensor water intrusion issue at the t/case, and finally c0327 may indicate a problem with the encode motor position sensor(available seperate from entire encoder motor). So like I said, lots of possibilties and not much you can do without a GM Tech 2 scan tool and access to the updated programming. Hope that help 'ya.

 

[Russell]

Well, we fired the truck up today, and everything seems fine...

Guess the truck was just complaining about it's first trip out when there was snow on the ground :P

My father always parks his baby before the snow flies, he hadn't done so yet, and the roads were too ugly to use my little V6 truck to move a car

 

[moneypit]

Mine did the same thing. It will come and go. Problem was at the wrong time. My bro's rig is now doing it as well. Sometime you just turn it off and all is fine. Also there were times on the freeway cruising 80 when it came on I looked at the selector and it said it was in 4lo......Good thing it wasn't! I am pretty sure there is a TSB on this (was on mine) but if you are out of warranty then it is on your dime.

 

[jayweb]

alot of times it is the pushbutton switch itself - or it could be the encoder motor as moneypit stated

 

[hammermachine]

Easy fix

I have a 03 2500hd, I've also had a two 2000 chevy 1500's. Anytime I had that warning light came on all I had to do was check/ replace the diff fuilds, especially the front one. Every time that solved the problem. I now check the fuilds once a month and I haven't had a problem since. I hope that helps.

 

[camarossguy2]

Hey guys!

My father and myself went out tonight to move a car for a buddy from his place to the tranny shop using my father's `03 Chevy 2500HD Duramax with an Allison automatic 6 speed, and some electric shift transfercase.

We got to his place, and shut off the truck, loaded up the car on the dolley. When we fired the truck back up, it gave an error message of "Service 4WD", and disabled the transfercase switch...

Does anyone have any ideas what might be the cause? It came completely out of the blue, and we hadn't touched the transfercase at all... The truck still runs and drives just fine in 2wd, and isn't making any unusual noises...

Thanks for any help!

Russ

If its an 03' its a alison 5spd...the 6spd didn't come out till 05' i think.

Id try reseting the computer.... unhook the batterys (both of um) for like 3 minutes or so...

 

[guz71]

a blown fuse wil cause that indicator light to come on. On the new vehicles, its pretty common for the switches to have to be replaced. I believe there was a TSB out for some of them....i think, but i know many people have replaced them.