"service awd" light. Problem solved!

[Carol]

You guys are great! I'm not mechanically inclined, but I was able to find, RIGHT ON THIS FORUM, discussions about the clicking symptoms when turning key "on" in ignition, (1999 GMC Safari, AWD, just purchased a few weeks ago), along with "Service AWD" light going on, (on lower left of dashboard)---and those symptoms thanks to you guys, was apparently pointing towards my Safari having a bad "encoder motor" (of Transfer Case).

I was going to FIRST have the transfer case Auto Track II fluid changed, but a little voice in my head (thanks to you all!) said--ask my local mechanic to run his code machine on my minivan, BEFORE getting the new fluid put in:

So, this morning, I asked my local mechanic in Granby, CO (Mike) to check codes, and "voila!", his excellent code machine said:

C0310, Motor A/B Circuit Open!!! That was what others here have already kindly shared, about resistance problems (goes over my head, regarding exact particulars) between A & B on the transfer case "encoder motor"!!!

Mike ordered a NAPA re-manufactured (NOT Dorman!!) Transfer Case ENCODER MOTOR, and he will put it in, along with brand new transfer case fluid, tomorrow morning! He thinks the clicking sound, when key is turned on, in ignition, might be coming from the TCCM (Transfer Case Control Module), located low down on the left, near the interior fuse box.

I just want to thank you all, again, for your great and generous comments here! I too, will let you know how long the "new" Transfer Case ENCODER MOTOR lasts!

[AstroWill]

He thinks the clicking sound, when key is turned on, in ignition, might be coming from the TCCM (Transfer Case Control Module), located low down on the left, near the interior fuse box.

That clicking is the tell tale sign of a bad encoder motor. There are cheap bluetooth scanners that you can get for $20something from Amazon(even cheaper if you want to get it shipped from overseas) that will read those codes for you on your phone/tablet. I use Scan Gauge Pro ($4) from play.google.com on my Android tablet/phone, it has the extended codes as well as all the standard stuff.

As soon as I have a little extra cash, I'm buying an UltraGauge, mentioned in another thread here. See http://www.ultra-gauge.com/ultragauge/index.htm

I wanted a tach, but this not only has a digital tach, but a full scanner, including the ability to reset codes. And only $60!

The wired one is a decent deal, but screw them on their bluetooth version they are freaking insane, $80 my ***. If you shop around you can get a bluetooth adapter for under $20 and then choose your own software.

[romeroom]

I realize this is an old post. But just in case (no pun intended)

I have also been getting a Service AWD light on. Two questions:

1. Is it a encoder motor replacement a difficult repair to do?

2. At a local Oil and Lube place, I was told the differential and transfer case fluid are the same. Does not sound right? Please confirm.

Thanks.

[thegreenmachine]

I realize this is an old post. But just in case (no pun intended)

I have also been getting a Service AWD light on. Two questions:

1. Is it a encoder motor replacement a difficult repair to do?

2. At a local Oil and Lube place, I was told the differential and transfer case fluid are the same. Does not sound right? Please confirm.

Thanks.

Yes it's fairly easy to do. You have to unbolt the front prop shaft to get at the 3 bolts.

10mm and 15mm iirc.

The transfer case takes autotracII, not gear oil, or atf.

Rear diff in my 2003 takes 75/90 synthetic and the front diff is standard 80/90 gear oil.

[AstroWill]

I have also been getting a Service AWD light on.

Just having an AWD light on does not mean that the encoder motor is bad, even though their failure is quite common, you should always check the codes and do a diagnosis.

2. At a local Oil and Lube place, I was told the differential and transfer case fluid are the same. Does not sound right? Please confirm.

This is why you should do your own work. This kind of information is in the user manual viewforum.php?f=110

Here is an example of one of mine:

user manual

example.png (146.82 KiB) Viewed 1179 times

[romeroom]

Thanks to all of you who have responded.

The "Service AWD" light is on now all of the time. I have a cheap OBDII scanner and it says nothing about the Service AWD light. I also get the clicking in lower left near the driver's feet upon key ignition.

1. What else do I need to do to confirm it is a bad encoder motor? I don't really feel like taking it to the dealer to have them charge me $50 - $100 to connect a specialty scanner and read the code.

2. Major stupid question: If I end up replacing the encoder motor, do I need to remove the old transf fluid?

[AstroWill]

1. That clicking is quite the indicator, it's pretty much confirmed right there. You have to use a tool/software combo that does the extended codes, a lot of the cheap handheld ones don't do the extended codes. See my sig link for what I use(bluetooth adapter and ScanGaugePro). or viewtopic.php?f=70&t=23185
2. No, you don't.