Bypassing 4WD ECU

I have a project in mind and need every expert’s knowledge. This is about the 4WD system of the Tacoma giving trouble to almost everyone. So recently, with 145,000 miles of running time for my 2006 Tacoma V6 double cab, the 4WD gave up on me. Tried every options, tricks and fix from the forum but to no hope in the horizon. It was regularly used on trip to the Texas Gulf.

The project I wanted to start is to have “manual switch to the front and transfer case actuator”. I’m not going to the FJ option since that needs major modifications.

First question: can I bypass the 4WD ECU?

The idea is to have an On/Off switch instead of using the knob and going to 4WD ECU. I think the main culprit to this 4wd problem is the ECU getting confused. The mechanical problem is easily fixed by replacing the parts with a new one but never a single solution came up to solve the electronic part of it. In somewhat I’m trying to make an analog process for the 4WD system.

Or is this a “not gonna happen” moment?

Thanks

 

Best fix is FJ t case and a fj diff sleeve to bypass all electrical

 

This.

But if you don’t want to go that route, you need to know what your problem is first, which you haven’t said that you do.

 

Did anyone diagnose what is wrong with it? I mean it is an electric shift system which isn't the best but all it takes is one microswitch in any component to hang the entire system up.

What's is doing and what has been tested so far?

 

There's a diagnostic test to manually fire the actuator to put it into the 4WD modes. I'm sure you could just make this more permanent of a test by using a standard relay.

Look at #7 on this PDF. I just printed/saved the whole works. https://gofile.io/?c=D0VnTb

Edit: I'm sure you're aware, but there would be nothing stopping you from sticking it into 4LO at 80mph down the highway. I would suggest adding a cut off key or something to activate the switch(s) so you or someone else doesn't accidentally do it.

 

You're intentions are good but your diagnosis is off. The 4WD ECU is almost NEVER the problem, it's getting "confused" because of the input sensors. The stock 4WD has a time delay built in for these items to change state, but alot of times they will never change state because they have a high contact resistant or are sluggish due to water intrusion or failure due to moisture.

You can bypass it with a few DPDT switches but if your actuator is gummed up and won't move, it won't help the problem. The only surefire way is to go all mechanical, eliminate the sensors as control items and use them for indication only (4wd and 4LO engaged on dash icons)