2005 AWD Problems

[gpen2]

Just got a 2005 AWD Astro Van...when I got the van the Service AWD light did not come on during the ingition sequence... so I changed ATC fuse and service AWD light came on. IT was only working in 2WD becuase of how it handled in snow.
I have a 3rd party warrenty so I sent it to the shop they recommended for tranny work. They told me the AWD transfer case fluid was clear and good.... all components good ...its electrical we cant help. Warrenty told me electrical not covered.

I took it back to the used car lot where I bought it and he sent it to an electrical place. They tested the error codes and found the encoder motor shorting to ground, so they replaced the encoder motor (actuater) they also had to flash/programm the BCM.
I got the Van back and the light is out but it now stays in AWD all the time, no light on dash but it hops and chirps when turning the wheels on dry pavement. I pulled the ATC fuse to see if it would stop the problem... it didn't it still is AWD engaged without the fuse.

Is this a mechanical problem? or electrical?

What tells the encoder motor to engage the AWD?



Help

[ihatemybike]

It sounds like the encoder motor is somehow stuck in the activated position. I'd try pulling it out, then test driving it to see if the problem goes away. If it doesn't, the clutches in the TC are sticking somehow.

[Corsemoto]

It's probably not a bad idea to check the transfer case and make sure the fluid is blue - Auto Trak II.

[strangerock]

Did they say why they had to program the body control module?... The encoder motor replacement wouldn't require any programming.....

['cudapaul]

There is a GM TSB for problems caused because of the wrong fluid in the transfer case.
It has been discussed on this site many times; you can search for it

Basically, as Corsemoto stated, replace the the transfer case fluid with GM's Auto Trac II fluid from the dealer.
Drive 100 miles, and do it again. That should take care of the problem.