3rd Gen Multi-Function 4WD ECU Spoofer

Ok I think we are saying the same thing a little differently. Essentially the more factory off road options on the truck, the more the spoofer would have to handle to make it work and function like factory in terms of the dash lights and communication. For instance my sport life over here I have much less conditions that have to be met.

Appreciate the feedback. Can't wait to see where this goes.

 

Correct, since you have less factory 4wd features, your spoofer will simply do less. You could still use a spoofer with every feature mentioned in the original post, just the ones that don’t apply won’t do anything. Like when I swapped to the non locker ECU, my locker switch still ran to the ECU like it did stock, but all of a sudden the switch was dead. The switch only provides a ground on one pin, and it was still don’t that, only the non locker 4wd ECU doesn’t do anything with that request. It’s an easy way for Toyota to keep all the wiring the same, and then plug in a proper solution depending on what each truck is equipped with.

I too am pretty pumped for this. I wish I didn’t need to grind the back of my transmission for the transfer case. I’m tempted to only eliminate the ADD for the time being. I do want the FJ tube for sure and that’s cake to delete. Transfer case is a bigger deal. Would be great, just not sure I really want to go that far with the grinding and making the shifter work. We’ll see.

 

@BLtheP is correct, the box I’m working on will work on all trims. Luckily, I have an OR trim, so I’ve got the rear locker to play with while testing. I will be testing and verifying everything with my truck in about 2 weeks (don’t want to risk messing with it until after a trip into the mountains at the end of this week) and then I’ll send off my board design to get a sample PCB.

@ClassyTacos I think most of us with 3rd gens agree that Toyota made the wrong call using the crappy actuators and should have given us a stick. The FJ case is a good option, but such a drastic mod for the application in my opinion. After I get these boards tested and manufactured, I’m going to put all of my free time into designing a mechanical solution to delete the actuator and keep the factory tcase, but it’s going to be a while.

 

Sub’d!

I’ve been running my FJ case for about a year now. I kept the actuators plugged in and zip tied out of the way but I would love to ditch those things and have the fj sensors talk to the computer.

 

Interested, seems to be quite a few ADD failures all at once these last couple of weeks. The force override feature would be nice, along with anytime locker as definitive needs.

2LO selection and the digital status display would be a nice add on for luxury.

 

I don't believe the OP has said anything about the dash lights working with his mod. That would require a CAN interface circuit, I believe he said he was not addressing the CAN at all.

 

OP doesn’t need to do anything with CAN. He needs the manual transfer case and his spoofer setup to properly report transfer case position to the 4wd ECU. Once that is accomplished, the 4wd ECU will continue to turn on the lights at the combination meter via CAN. So instead of actuator switches telling the 4wd ECU the transfer case position, the FJ stock switches combined with the spoofer spitting out some logic will fool the 4wd ECU into thinking the stock transfer case is in place, and it will properly know the position it’s in in order to light the correct light on the dash.

 

Any photos of your shifter? Not exactly relevant to the thread but would be nice to see another example and OP having a manual probably wouldn’t hate the input either…

I really want to swap, just don’t like the grinding part.

 

^Nailed it!

@Toycoma2021
Leaving the factory 4WD ECU and connecting spoofs to it allows us to use simple circuitry to trick the 4WD ECU into believing that it’s operating normally (or how we want it) and it will report everything back to the main computer over CAN for us.

 

I feel most issues are normally with the ADD actuator, and water related at that. Either a ripped hose or the breather not being high enough in the engine bay. I replaced the hose from the ADD to the hard line then from the hard line higher up in the engine bay. Used some braided hose and nice hose clamps. Would love a manual no actuator option but i think this is the best you can do to keep it functioning

Good video showing/explaining it
https://www.youtube.com/watch?v=CGG-I4f04aA

Hose clamps i used

$11 Swpeet 12Pcs 14MM-16MM 304 Stainless Steel Mini Fuel Injection Line Style Hose Clamp Assortment Kit Perfect for Automotive, Agriculture, Plant & Construction

https://www.amazon.com/gp/product/B07YZD8SR4?ie=UTF8&th=1

 

Here you go. I was pretty concerned about the grinding at first, but then I realized that (at least on mt’s) where we need to grind has no chance of opening up into the guts of the trans - behind where the clearance needs to happen is the trans shift linkage, which is self contained, sealed off from the gearing. Pull the trans shifter to see.

A ball-end, single cut carbide burr was the ticket, but if I had to do it again I’d likely put marking paste on the shift rods and try to install the case. It won’t go in all the way - the gap between trans and case is roughly the clearance depth required, and the paste will leave marks where cutting needs to happen. Then some quick work with a 9/16” drill bit.

The other thing that made the job a lot easier was having the truck on 8” ramps. It allowed me to sit comfortably in the trans tunnel to do the cutting.

The FJ sensors are ball detents that work just like the detents that hold the shifter in gear. 2 wires off of each.

 

I would agree, the ADD seems to be a bigger problem than the t-case. Both have shown issues, ADD seems to be more common. The ADD is the one that makes the final completion of the shift take forever too, as the splines have to line up before it finally completes the shift and actually transmits torque to the front wheels. With the ADD gone, shifts would be almost instant, almost all of the time. That would eliminate the biggest failure risk and make the 4WD much quicker, which I would like and probably be mostly happy with. I'd still like the manual transfer case too though, it's just less priority.

I would do it the FJ tube method if I did it, and I want to currently, just don't know what to do about the fork in the mean time other than tie it away and let it keep actuating without doing anything. I have considered doing that.

 

Thanks! That turned out great. Good info on the grinding too, I assumed we would be not far away from getting into the gear oil area.

I am going to be swapping to the RC60F as soon as I can get my hands on one, so I will probably do my grinding out of the truck, if i can get a transfer case and have the input swapped in a reasonable amount of time.

 

Agree seems to be more so the ADD but you do see some transfer case actuator problems too. Makes me wonder if you could spoof it why couldnt the current ADD be permanently engaged. Spoof the computer everytime to trick it to "shift", i have no idea if this could be possible or what strain it would likely have on the stub shaft.

 

It takes longer to remove the bolts and crack the case open than it does to swap the inputs and modify the rods for twin sticks! Just have a quality set of snap ring pliers.

I’ll mirror everything about the ADD being the main failure point. When I swapped to a solid shaft I was really surprised to see some decent play in the shaft where it needs to interface with the stub shaft- it’s only supported by the shift collar and cv bearing. Additionally, for something that can be shifted in motion I’d expect to see some sort of synchro. Nope, just some quite small lead-in angles on the gear teeth. No wonder it never wants to work.

 

Spoofing ADD will be possible with the box I’m building. If the ADD fork can be mechanically and reliably held in the locked position, I don’t see any reason why we couldn’t/shouldn’t just remove the wiring harness from it. I’ll be picking it off before that point, so it makes no electrical difference.

I think what I’ve read in old threads discussing ADD delete is more of a concern of the front drivetrain being connected to the road at all times, and there’s a front manual hub kit I see from time to time to address that issue.

 

For this I tend to think letting it spin is the best call. Haven’t seen a reliable hub kit for our platform and the one that was out for a while wasn’t reliable and has been discontinued. I see no downsides to letting it spin, other than minute added wear on the front diff and maybe a tiny hit on fuel mileage. Which I would think is negligible since we drive on the rear diff all the time, so it’s always spinning.

The only true downside I can see would be the loss of 2Low functionality, but I’m okay with that.

 

Good video showing the issue. Please do NOT use the soaker hose shown in this video. From the description for that PN from Lowes.com:

• Porous non-pressure compensating material gently seeps water out of the entire line of tubing
  

 

Yes this is what i used, actuator could still crap out but gave me a piece of mind has to count for something

$21 10FT 4AN Braided Fuel Line Hose Nylon Braided for 1/4" Tube Size

https://www.amazon.com/10FT-Braided...+hose+br,aps,116&sr=8-16&th=1#customerReviews

 

In your first post you say an "Anytime Locker" is part of the package. In the stock form the system has to be in 4WD Low to engage the Locker. Sounds like one possibility is you are wanting to spoof the 4WD ECU into believing the truck is in 4WD Low so the Locker can be engaged. That can certainly be accomplished by manipulating both the connectors/wires at the ADD and the Transfer Case or better yet at the 4x4 ECU, but then the dash lights for 4x4 and 4x4Lo, as well as the 3 to 4 safety features that get deactivated will be on, i.e. not showing the "true" condition of the truck. I can imagine this would be unacceptable to many OCDers.

The other option, which is currently used by others, is to independently supply power to the Differential Lock Coil to lock the locker. The Transfer Indicator Switch T13 on the differential will close signaling to the 4x4 ECU the locker is locked, but the 4x4 ECU does not recognize this input as it did not request the activation of the locker and is not looking for a closure of Transfer Indicator Switch T13 and thus the 4x4 ECU will not tell the Combination Meter to light the LED saying the locker is indeed locked. Interestingly enough there is no error displayed in this condition. i.e., the locker is locked, the locker is telling the 4x4 ECU it is locked, but the ECU can't tell the dash light to light telling the driver it is locked.

We both have 2021 ORs, if your testing is showing different results, we have very different 2021 OR trucks?

I just reverified my memory as to the closure of the Transfer Indicator Switch T13 by going to the EB3 connector in the engine compartment fuse box and grounded the Blue wire in cavity 17. Same as getting under the truck and shorting out the two wires.

I looked into doing a similar design sometime ago, but during my testing I really did not like the Toyota Electric Locker engagement. I will be putting in an air locker, which in my other vehicle activates and deactivates so much quicker than the Toyota electric one.

FYI:
In my testing I found Toyota is using a 1KHz PWM driver to activate the Locker. Most of the PWM power supplies that have been used have been 15KHz, I think Toyota uses the lower frequency to lessen the possible noise generated on the other circuits within the vehicle, thus having less problems. This would apply if you were wishing to utilize the "Differential lock coil" in the same way Toyota does. Some have supplied a constant DC voltage to the lock coil to lock the differential. So far generating no problems that anybody knows about.

In preparation for doing an Anytime Locker I did this:
https://www.tacomaworld.com/threads/anytime-rearlocker.822600/page-4#post-29611032 Post #63.

I suggest a breadboarding of your circuits before having PCBs made.

Depending upon time, I'd be up for testing and proof-reading schematics to the best of my ability.