No front traction on 4x4 Auto

[wollimann]

1998 Explorer V6 SOHC 4x4 TC BW4405 TOD VIN 1FMZU34E5WUB15483

Hi,

a courious problem accured, don't notice till now. But now it is snowing and the front wheels have no traction on 4x4 Auto mode. In 4x4 high and 4x4 low the front axle do its job. Usually you feel it while the front axle become torque from TC.
It seems, that the magnetic coil becomes no charge in 4x4 auto mode.
Did anyone heard of such a problem?

thanks in advance

Wolfgang

 

[SoNic67]

See the attached diagram for troubleshooting:

https://drive.google.com/file/d/0B3Ausvq8G8j-ZUpPb3RWcUZLb3c/edit?usp=sharing

I would start with 'Torque On Demand' module.

 

[DjDom]

I think you don't understand how 4x4 auto works.

4x4 Auto is not all wheel drive.
Your truck is in rear wheel drive the whole time, if it detects that the rear wheels are slipping, then it will make the front wheels spin. They are not always on, and the time it takes them to turn on is quite a while sometimes.

Just use the 4x4 switch if you need 4x4.
4x4 Auto isn't that reliable, and many people disconnect it..

 

[imp]

I think you don't understand how 4x4 auto works.

4x4 Auto is not all wheel drive.
Your truck is in rear wheel drive the whole time, if it detects that the rear wheels are slipping, then it will make the front wheels spin. They are not always on, and the time it takes them to turn on is quite a while sometimes.

Just use the 4x4 switch if you need 4x4.
4x4 Auto isn't that reliable, and many people disconnect it..

How? imp

 

[SoNic67]

I assumed that he tried it on snow, not dry pavement:

But now it is snowing and the front wheels have no traction on 4x4 Auto mode

 

[DjDom]

How? imp

Brown wire mod. Turns off the Auto 4x4 and makes it true 2WD.

 

[DjDom]

I assumed that he tried it on snow, not dry pavement:

I've noticed mine doesn't do it much in snow.
I can even floor it on dry pavement and spin my rear tires, but 4x4 won't engage.
In snow, I can drift around for a while before 4x4 engages..

 

[Robman]

ABS light on by any chance ?

 

[wollimann]

Hi,

thanks for your answers and the diagnostic diagramm!!!
I think i quite understand the 4x4 auto mode.
According to my 97ex (speedo on TC) your really feel/hear it when the front axle is working in auto mode. It takes only some milliseconds to activate the magnetic coil in TC. Also have a Brown Wire Switch with control LED, and you can see the LED swallow up when 4x4 auto is on.

But on my 98ex (speed sensor on rear diff) there is no action/traction on a slippery surface (standing in front of a small hump). And there is no ABS light flashing in any situation. Now it's snowing a little bit and i can drift around with no front power.

I am not so firm in reading electric diagramms and i didn't have a special OBD interface to read out any trouble codes from transmission. Only have a OBDLink USB interface with scanmaster elm software. No support for transmission and so on, only could read/delete standard errors (e.g. Knock sensor -> last error on my 97er).

If the rear diff sensor is involved in 4x4 auto mode, i will give him a chance. But it's not so easy to get a new one here in europe, will see if rockauto has it.

Greetz Wolfgang

 

[SoNic67]

Only have a OBDLink USB interface with scanmaster elm software. No support for transmission and so on, only could read/delete standard errors (e.g. Knock sensor -> last error on my 97er).

Use the http://forscan.org/, it is a much, much more powerful tool. Free.
I posted the link before but... I guess it wasn't deemed important enough for a 'Sticky'.

PS: There are TWO sensors involved. One for rear and one for front axle.
Condition to activate 'Auto' is that 'rear' speed is zero AND 'front' speed not-zero. If the front is zero all the time, 'Auto' won't work (it 'thinks' that you are stopped).

 

[wollimann]

Use the http://forscan.org/, it is a much, much more powerful tool.
I posted the link before but... I guess it wasn't deemed important enough for a 'Sticky'.

PS: There are TWO sensors involved. One for rear and one for front axle.
Condition to activate 'Auto' is that 'rear' speed is zero AND 'front' speed not-zero. If the front is zero all the time, 'Auto' won't work (it 'thinks' that you are stopped).

You mean the two sensors in the transfer case? Only these sensors are responsable for auto 4x4?
Forscan i will try (free software?) -> thanks so much!!!

Wolfgang

 

[SoNic67]

Yes, those two are connected to 4x4 module. The sensor in the rear axle I think has a different role (VSS).

 

[imp]

Ford Shop Manual Info

Here is what the Ford Shop Manual says under "vehicle does not operate correctly in 4X4 AUTO"

1) Battery junction box fuses 17, 20 A, 18, 20A
2) Central Junct6ion box fuse 12, 5A
3) Mode Select Switch
4)Transfer Case Shaft Speed Sensors
5) Four Wheel Drive Control Module
6) PCM
7) Stability Assist
8) Circuitry

Note that this info is from my 2004 Explorer Manual. imp

 

[wollimann]

Tanks so much for support! I will keep you informed!
Oh these old riggs

Wolfgang

 

[deweyville65]

Explain this one guys. I've been trying to figure this out for over two years. 96 Control track. Jack up all four wheels,at same time, front and rear will spin. Lower front, will not try to pull off jack stands. raise front only, front lockout engages, and cannot turn front driveshaft by hand past about 10 degrees either direction. Did brown wire mod with double throw toggle switch and led light. Led shines full bright when switch in full power mode. Light changes intensity when in auto mode, indicating computer control. From what I have been able to determine, the electro magnetic clutch is only partially engaging, even when in manual mode. Any ideas? I have no problems getting around with it in slick conditions, thanks to limited slip diff.

 

[imp]

Explain this one guys. I've been trying to figure this out for over two years. 96 Control track. Jack up all four wheels,at same time, front and rear will spin. Lower front, will not try to pull off jack stands. raise front only, front lockout engages, and cannot turn front driveshaft by hand past about 10 degrees either direction. Did brown wire mod with double throw toggle switch and led light. Led shines full bright when switch in full power mode. Light changes intensity when in auto mode, indicating computer control. From what I have been able to determine, the electro magnetic clutch is only partially engaging, even when in manual mode. Any ideas? I have no problems getting around with it in slick conditions, thanks to limited slip diff.

All I can say is, if you ain't got snow over there now, you will pretty soon! imp

 

[SoNic67]

From what I have been able to determine, the electro magnetic clutch is only partially engaging, even when in manual mode. Any ideas? I have no problems getting around with it in slick conditions, thanks to limited slip diff.

Worn clutch plates?

 

[deweyville65]

Worn clutch plates?

Thats my thinking, and since I do not need 4WD, I'm going to quit worrying about it. Thanks