The check AWD light has been coming on intermittently for 6 - 8 mos. now. Now it is more than 1/2 of the time. When the light is on--no front engagement. No light and the front engages. At startup of the vehicle, there is a sound--maybe from the glovebox area--kind of sounds like a clicking sound; like it is performing a check of the system. Right after the sound is heard is when the light will come on the dash. Had a real good tranny shop look at it and the code told them it was a lack of communication with the AWD system and they suspected the encoder motor. I ok'd them installing a pulled encoder motor--but it made it worse--so they put the original back in. Of course, it worked at that time (because it will work sometimes). So anyone here have any experience with this? I'm hesitant to pay for the new unit if it is not the part I need. Refurbs are an option.

`01 Bravada Vortec V6, np146 tc (I think), fresh fluid about two years ago

 

I have read about TCCMs that have corroded connections and this causes intermittent problems. This applies to SmartTrac and 4WD TCCMs.

Most owners were able to clean the connections and restore full operation.
This is a free fix, so try it next.

BTW, TC fluid is scheduled to be changed every 50k.

 

How many connections are there--do you know? I can look around down there and see. Thanks for the idea--I will give it a look.

 

Well, finally got around to checking/cleaning the connections. Found some corrosion on one pin of the four pin connection. The 32 pin connection looked quite clean. Took some electronics cleaner to everything and lubed both connections with dielectric grease. In the end, the Service AWD is still on--now seemingly all the time. When the ignition is turned on, there are noticeable clicks (four) from the TCCM before the service light comes on. One local mechanic I spoke with said to give the cleanup a try but it could be a bad shift motor. A local trans shop that I work with has looked at it a couple of times but my opinion is that they are stumped. When asked what their confidence level was with repairing this--the owner said, "...that's all wheel drive." I would like to get this repaired before the snow flies as my wife drives it daily and the AWD is great on slippery roads--plus it prevents me from having to run down the driveway in the snow to park her auto for her Anymore tips would be appreciated.