99 Trooper TOD Green Rear Wheels Flash then CHECK but 4wd Works Fine

[fakemilkman]

Here's the problem: When I turn my 99 Trooper 3.5 with TOD on, the two green rear wheels in the TOD diagram flash slowly. After driving for about 2-3 mins the CHECK light comes on just below the TOD diagram. It seems to run and drive fine and if I push the Auto 4wd button the check light goes off and none of the wheels flash. Does anyone have any idea why this would happen and what I need to check?

[Firemanbob]

I have been having the same problem but I have a 98. I hope someone can help.

Bob from Chicago

[Ajaxmotors]

My "check" light flashes under the TOD sometimes when truck is cold. I can't find a consistent pattern or # of flashes. Seems to drive just fine...

[gt-1]

how did you fix the problem

[fourwd1]

Has anyone had the OBD-II codes checked when this is happening?
A generic /parts store reader wouldn't do, it would have to be one with an Isuzu specific module.
FWIW, I haven't seen this on my 2000, but I only drive it once or twice a week.

[fourwd1]

WOW, I spoke too soon.

I now have a similar problem. The 2 rear wheels and the word AUTO in the TOD display flash, but no CHECK light below the TOD display.

This also happens when I put it in 4-LOW.

I'm going to take my own advice and get the OBD codes read at the dealer.

Any of you guys resolve your problem ??

[bamashooter]

No idea yet; Here's an explanation with graphic on the operation of TOD along with an interpretation of the "green" lights.

http://www.autoworld.com/news/Isuzu/Torque.htm

[bamashooter]

Read a post earlier in another forum where an individual had a problem very similar to yours. Performed a couple of back to back transfer case fluid changes and the problem went away.

[fourwd1]

My problem isn't in the t-case, when I put it in LOW it is in LOW range.
The problem is in the front axle, either it isn't locking up, or it is locking up and the sensor is bad and doesn't know it's locked.

I need to put all 4 wheels in the air to see, and go from there. Maybe tommorow. I know i can dis-connect the 2 vac lines to it and force it to lock, if need be.

[fourwd1]

UPDATE

As I suspected, the front axle wasn't locking. Wasn't the the switch that reported back that the axle was or wasn't locked.

I found that the Connect (Lock) vacuum switch (the grey one?) didn't hold vacuum, had an internal leak.

Unfortunately, parts stores don't carry anything remotely close (I did find a 2-port switch, but no 3-port ones). So I had to pay $241 from the stealer for the 2 switch assy