4WD Not Working...

Alright. Well at this point I think I'm going to let the dealership solve the problem.

 

Remove the actuator and clean it first

 

This sound weird but this may help: the battery may be uncharged or maybe the battery terminals are not on right. And here's why I think this.
I bought my '01 and the same thing happened to me. But I never tried 4wd at high speeds. However the only way I could get cruise control to work was when I was doing at least 70mph. When I changed out the battery terminals, the problem fixed and I am now able to turn cruise control on.
My 4WD doesn't work still, but it still goes into 4lo gearing when in 4lo. I just need to figure out why the front tires aren't locking. But checking the battery would be my first look because before I changed out my terminal, it wouldn't even go in the 4lo gearing when in 4lo.

Sorry for the long explanation. Trying to type while busy is hard.

 

Well the dealership said it is the 4wd computer so I got one and changed it but still not working. I'm really thinking it's the actuator.

 

sorry you're still having to fuck around with this issue, if I understand right, you have the throttle-by-wire setup w/electrical engagement , is it just electrical or is there a vaccum (pnuematic) assist ? If so, check all air/vaccum hoses on or around the acuators location..

 

It's just electrical. I'm going to test the damn actuator and go from there. I'll check back when I figure it out.

 

Bringing up an old thread...just got back from college and still don't have 4wd. I got the new 4wd computer and still nothing. I just tested power to the push button and there is no power in or out. Any ideas?

 

Did you check continuity on the 2-4 switch? Should be closed (show continuity) with the switch pressed in.

Since the 2-4 switch grounds out pin 4 of the 4wd ECU you probably won't see voltage at either pins.

Check continuity on the push button lever and report back.

 

Okay so got the truck back from toyota for a second time. Here is what they said...
"First visit. Found that the add was locked but the transfer case was not. Checked the switch input signals. The push button switch works and the 4wd light would come on when tested. Tl2 wire did not have power to it at any time. Possible problem with the 4wd ecu. Try that first."
I replaced ecu and still nothing.
"Second visit. Found that the front differential is locked into 4wd. The transfer case is in 2wd. Tried to unlock the front add actuator and the actuator operated and the differential did not unlock. Found that there is no power to wire dl1 and dl2, add position switches. 2-4 select switch operates normally. The front add actuator needs to be checked. The switch circuits need to be tested as well."
What do you guys think is the best next step?

 

Check incoming voltage at IG (pin 12) at the 4wd ECU. If no voltage is present recheck the 20A 4WD fuse. If the fuse appears good test voltage at either leg of the 4WD 20A fuse holder.

 

Okay will do. I will report back

 

Where is the 4wd ecu on this truck?

 

Here are pages from the factory 2003 shop manual FWIW

 

Any idea where that correlates to in the truck?

 

if you are referring to the "4WD ECU" its shown here in the 2003 Manual, which in the 2003 V6 was behind the center console.

 

Ok thanks. I have had a time trying to find it.

 

Youre welcome.
I admit that its hard to pin down where it is on that model.
There were changes between the 2002 and 2003 Tacoma models.
It is either behind the center console/ash tray or behind the glove box.
As the glove box may be easier to remove I would check that first just in case

Here is a thread to check:

 

All years, it's between the stereo and SRS computer.

 

Looked under there tonight, found a green box and I think the other was silver. Didn’t get a chance to try to get either out.

 

Yessir. Green box. That's the 4wd ecu.