3rd Gen Multi-Function 4WD ECU Spoofer

I just want to use MTS and/or a locker in 4 high

 

The FJ cases I’m looking on eBay (automatic part time) appear to have 3 switches on them. So maybe they do report high and low, but I didn’t see that in the wiring diagram.

Edit, whoops I missed it, there is indeed a L4 switch. So 4h, 4l, and N are the 3 switches on the tcase. They all should be 2-wire.

 

I took a look at the diagram too and it will be crazy easy to tie in. If I'm scanning over it correctly, it's just a pull-down (to ground) for the switches you named, and the manual case has an additional one for the center diff lock. This is actually very similar to the actuator assemblies on our tacos.

 

I'm including a controller for the rear locker to be used in 4Hi.

Since I have a manual trans I hadn't even thought about MTS. I actually didn't know it only works in 4Lo, is that correct?

If it only works in 4Lo, I would personally be very hesitant to try and use it in 4Hi because I bet that it's counting on: specific RPM = specific wheel speed, and adjusting traction system accordingly. Like for example on my truck, I would never want to use ATRAC in 4Hi, it would be way too jarring and not very useful. @BigWhiteTRD do you have any input here?

 

If I understand it correctly, the AT (part time) case has 3 switches (4H, 4L, N), while the MT (full time, no ADD) has either 1 or 2 (I think 2: center diff lock, 4lock low). I don’t think 4lock low actually does anything besides enable the ECU to allow the locker to work. I don’t think the ECU does any sort of turning on a light for low at the combination meter.

they all seem to pull to ground, yes. Then the ECU grounds the combination meter for illumination.

I would be using the automatic trans part time FJ case and swapping the input on it to work with my manual transmission. So mine would have the 3 switches, though I think the neutral one could be switched because I don’t need the neutral reporting that that did in the automatic FJ.



I was under the impression that the reason we can’t simply just wire up the FJ switches to replace what the actuator switches report is because the actuators report several times across the sweep or something like that. In other words, the input from the FJ switches would be too “dumb” for what our ECU wants to see. I could be completely wrong on that but I want to say that was part of the problem.

 

You can only activate it in 4L. Not sure why, my wife’s Highlander has a mud and snow traction any time. Could be difference in AWD vs 4x4.
I rarely drive in 4L unless off-road or really shitty road conditions, but am in 4H most of winter and would be nice to utilize MTS on trails that dont need 4 L, or mountain roads when 4H need a little traction boost

 

That is THE problem that I went after first. To be clear I wasn't saying it could be done without a spoof of some sort, but with the design I've got it will be crazy easy to take the FJ case switches as inputs to the board instead of the 4WD mode select knob. I've already got the timing and sequence of the switches and it will be a cakewalk to send that to the 4WD ECU when you change drive modes on the FJ case. It's exactly what we were both hoping for.

 

Well, great news then! I’m still not pumped about grinding the back of the transmission, but if that’s the only hang up besides the diff tube, then I’m all in….

 

Way behind on most of this discussion, but I would be concerned ATRAC and MTS and Crawl Control would behave in any reasonable way in 4hi.

All 3rd gen 4wd trims should have TRAC in 4hi by default, that is as good as you should expect in 4hi, I would not recommend spoofing truck so it thinks it's in 4lo (when it is actually in 4hi) and engaging MTS/ATRAC, but just guessing here... never know until you try. (I bet you will throw a code, because truck will realize it's in wrong condition because of high wheel speed)

 

A manual transfer case and add delete would be amazing, ive seen it on 2nd gens but any clean installs in a 3rd gen for the transfer case shifter? Would be great but unless its a purpose built rig who wants a hacked up center console

 

Not sure if you saw my last comment or not but I had you confused with a 5MT owner.

With the automatic it seems pretty touch to get the shifter to look good. It turns out okay on the manuals. You end up having to hack up the console on the autos I’ve seen. Not pretty, but not sure of any alternatives.

 

Ah ok yeah did not notice you were a 3 pedal, all the ones ive seen for 3rd gen autos were hacked. Its not that hard to make your own linkage to bend it where you want, very clean on 2nd gens though. Sad that we are looking to mod the truck to get a non motorized transfer case. Too many idiots in the world today to have a lever anymore i guess, toyota went 1/2 modern, 1/2 keep the parts we have. Manual parking brake, drum rear and shit actuators that control the 4wd.

 

Has there ever been a thread of people discussing deleting the actuator on the 3rd gen taco tcase? Like replace it with a mechanical linkage setup? Though the FJ case swap is awesome, it's such an extreme mod unless you're converting to all-time 4wd.

If not, let me get this project to the finish line and then..... hold my beer.

 

I wanna say a few looked into it and they determined that the internals of our case do not support being shifted by the lever. I don’t recall why or how they came to that conclusion. I agree it’s a pain having to source an FJ case and for us 6MT guys, do the grinding involved for fitment AND have to tear down the case so that its input will work on our transmission.

I personally think it would be cool to use the full time case from the manual FJ, but that would require lengthening and shortening the driveshafts by something like an inch. I forget what the difference would be. I’d much rather that than a part time case for my use though.

 

Went ahead and bought my AC control panel. They’re sort of hard to come by because you’re basically limited to a 2021+ V6 SR 2WD in order to get one without 4wd AND smart key AND automatic climate control (which is what I have). Almost all SR5 and above V6 have smart key, which limits you right off the bat. You need a V6 for climate control to be automatic and you need 2wd to be missing the 4x4 knob. Overall I did finally find it though.

55900-04122-B1

 

Thinking about this spoofer module more, I’d even be happy to at first only get a spoofer that lets me delete the ADD. The ADD is more problematic than the transfer case and is what I’d like to ditch most.

 

super interesting subbed.

I would imagine all of us with a TRD sport trim and down lacking ATRAC- factory lockers, the swap would be the easiest in terms of electrical, dash lights and ECU configurations.

As mentioned before a would want it to function as close to stock as possible. Manual shifts is how this should have come from the factory. Removing those tiny motors in the ADDs out of the equation is a huge confidence boost. And you get to remove the front stub shaft as a weak link in the front diff, the FJ tube is a strength upgrade.

It's all a fine dance here. I would be completely fine with hacking up the center console for another stick because of the gains with doing the swap.

 

Shouldn’t end up mattering which trim. The 4wd ECU handles it all the same no matter what brake booster the truck has. They all use the same connectors and the same wiring to each plug. For example, the trail special edition 4x4 has the locker and the vacuum booster. It should use the same 4wd ECU as the pros with the hydro booster due to the locker. All the stuff like ATRAC and everything else doesn’t matter.

Basically, all this swap needs to talk to is the 4wd ECU, which is not brake system specific. As long as it can do that and fool the 4wd ECU into thinking the electronic transfer case and ADD are there, then we are good to go. Nothing else downstream cares.

 

Yes, somewhat right, Depending on what mode you want to be in there has to be a path? If this then that and so on no? For instance, if you're not in 4lo then the factory rear locker won't engage, right? There has to be a work around for that.

Are you saying that one work around will handle all the different configurations available as long as the 4wd ECU believes it's in 4wd?

I'm not trying to argue or push some ego bullshit. I just like understanding.

 

The 4wd ECU handles all of that. It is the one that turns the locker on if all conditions are met. A sport has a different ECU that doesn’t support locker activation. On the locker trucks, it’s one pin on one of 4wd ECU connectors. On the sports and other non locker trucks, that pin is simply empty.

I have an offroad with the stock locker. For a brief time I swapped my axle to one I built from a second gen with a TrueTrac. Bunch of 4wd lights popped up on the dash because the 4wd ECU noticed the locker was missing. It wouldn’t let me use 4wd as a result. I thought the 4wd ECU out of a Sport/SR5/etc (non locker truck) and everything was perfect, it was as if my truck had no factory locker ever at that point.


It’s kind of like the 2 lo mod - the kits are all the same whether you have a locker or not. It’s just that the locker version uses a few more pins. The t harness on the spoofer kit will just need to have all the wires populated, but otherwise no functions will change whether you have a sport or offroad or anything else.



For something like you must be in 4lo for the locker, he will need to include spoofing equipment to address that behavior, but that function will simply not do anything on the non locker trucks. All the spoofer will need to do is provide a ground on one terminal as a fake 4lo indicator so it will turn on the locker.

I’ll add 4wd ECU part numbers too. “With offroad” means it has locker, “w/o” means non locker:

89533-04030 - 16-19 w/o off-road, 4WD
89533-04041 - 16-19 with off-road, 4WD
89533-04050 - 16-17 with off-road, 2WD
89533-04051 - 18-19 with off-road, 2WD
89533-04060 - 20-23 w/o off-road, 4WD
89533-04070 - 20-23 with off-road, 4WD
89533-04080 - 20-23 with off-road, 2WD