intro + help me with my blinking 4x4!

[Mr.TT]

Hey guys,

Just bought a 2000 4.0 SOHC XLT 4x4 Explorer for ski season... loving it except it has the dreaded 6x blinking 4wd problem! I've searched a lot on here for how to handle it so I just want to make sure I am heading in the right direction.

Symptoms:
-Shortly after starting the truck, every time, I will get the 6x blink.
-Predictably, switching into 4hi or 4lo does nothing as the GEM has cut off any 4x4 actuation.
-dealership wants $120 to pull the stupid code so I will start cheap and work my way up.

I read stuff about speed sensors. Please correct me if I am wrong here: There is on one the transfer case, and one on the rear diff that is combined with ABS? Are there any more? My speedometer works fine and I don't throw any other codes (ABS or CEL). Does this eliminate anything?

Sorry if my questions have been answered... I learned a ton by searching but hadn't seen anything about the total number of speed sensors and whether my symptoms indicate one over another, or perhaps a different problem altogether.

Thanks!!

 

[dogfriend]

There are actually 3 speed sensors, one is the VSS (vehicle speed sensor) which was relocated to the rear axle in 98 (it used to be located on the TC (transfer case) prior to 98).

For the flashing 4wd lights, you want to concentrate on the 2 speed sensors mounted in the TC. These sensors are read by the GEM to determine the front and rear driveshaft speeds - this info is used by the GEM to control the Auto 4wd function.

Some have reported that cleaning the 2 TC sensors has helped with the flashing lights - the issue here is that the sensors are magnetic and will attract any loose (steel or iron) particles floating around in the ATF. If the GEM can't determine the driveshaft speeds, it will set a DTC (diagnostic trouble code) and flash the 4wd light.

However, there are other reasons that the light could be flashing as well. It is best to get the codes read to know for sure. You certainly could try cleaning the sensors (and changing the ATF in the TC if you find a lot of particles on the sensors). It couldn't hurt.

 

[Ray Lobato]

You might want to try and unplug and plug the connections on the GEM. I once had this problem and reseating the connectors did it for me.
I would also try cleaning the sensors, like dogfriend said.
Please keep us updated as to what your situation is.

 

[Mr.TT]

Thanks for the replies. Even though I've read on here that disconnecting the battery doesn't solve anything, I tried it on a whim and it worked for me. Haven't put many miles on the car yet but it will engage both hi and lo range 4wd now. I'll start up on the speed sensors if it reverts back to broken.

 

[Steeda90GT]

I disconnected my battery, let it sit for 20 min and it has been fine for over a year now. Anytime I have a warning light of any kind i always do this (for every vehicle I own)

 

[Mr.TT]

I'm hoping that's all it needs. Drove it to work today and it's still functioning perfectly.

 

[Steeda90GT]

Yeah, it could've just been dirt, moisture or something that triggered the sensor. Give it a few months, you should be OK.