Rear Diff Lock Anytime Mod 3rd Gen DEVELOPMENT

That is my guess, but not sure. (That is the kind of thing where I was hoping for some help, as I wrote in OP. Somebody who regreared has had it open...)

 

Remember, I am not excited about this mod, so I don't have an important opinion on how complex we design this mod. Those of you who want to do the mod, need to chime in

First super important question.
Do we need to make sure that ABS and TRAC are disabled when the anytime diff lock is active? What do people think, any input based on how the mods worked on 2nd gen? I feel like toyota did it for a reason, but I don't know...

 

So if you don't care, then why work on it?

 

Because I designed 2 wheel low mod for 3rd gen by myself because I wanted it, and documented it on a new thread because of all the great work that goes on here that I have used. Literally more than twice as many posts requested anytime lock than said thanks or anything.

So I thought I would give it a shot and see if the 1/1000 who beg for it will put in even a hint of help to make it happen.

 

Even if the light was blinking, I wonder if the differential is locked...because I would assume if you are hijacking the power supply that it is still locking up, regardless of the status of ABS, VSC, and the indicator light...

 

In this case, the diff was unlocked. I left the ECU connected to the locker, I disconnected the lock/unlock indicator switch and ran it to my own toggle test switch.

My goal was to simulate for the ECU what it would be like to be driving along in 2hi, activate the anytime lock that would apply current to the coil and lock it, and have the lock/unlock switch indicate to the ECU that the diff was then locked. I figured that the ECU would detect the locker engaged, would flash the dash locker light, and would keep ABS and TRAC disabled. It didn't do that.

The ECU did flash the dash locker light, it did prevent 4wd mode changes (after a minute or two), it also had no 'TRAC-OFF' nor 'ABS' lights like you normally have in 4Lo with the locker active. I then did a brake check just to make sure, and it felt like ABS was active. So still feeding the lock/unlock switch data into the ECU while we do an anytime lock seems pretty pointless right now.

 

Not enough thanks given sometimes. I think I am unable to help more due to lack of technical understanding with the electronic side of things. I am mechanically inclined but not sure what kind of help I would really be.

 

@uhplifted

 

This can't be too difficult. The 2WD TRD OR has rear locker. Granted, it doesn't have the 4wd ECU, but there has to be a bypass.

 

You can do more than you think, probably. Alot of this type of reverse engineering involves doing a simple change or wiring spoof and seeing how the computer responds.

From my OP
Anybody willing to go check the disconnected coil resistance with an ohmmeter? Anybody willing to go jack up the ass end of their OR/Pro and with it locked, and then disconnect the lock harness and see if it automatically unlocks? Anybody willing to lock their ass, and then shut off the engine to see if it unlocks? Anybody willing to temporarily hook some jumper wires between the truck harness and the lock coil, and independently measure coil voltage, polarity, and current while attempting to lock and once locked to see if it matches the Techstream data? Anybody willing to reproduce the techstream data that I got?

 

Thanks for your efforts on this, really appreciated.

Do you have a copy of the 16+ service manual?

 

Yes
From this post if I recall
https://www.tacomaworld.com/threads...manual-availability-pdf.485229/#post-14862261

 

Right on, lots of good info in there. I found it particularly useful to read the diagnostic procedures on stuff such as the locker, gives a good idea on how the sucker is supposed to act.

 

Yep.
Agreed
On first page we hit some of the most important stuff without a doubt.
What we know so far

Lock Coil is energized with 12v
If the lock detection switch is not locked, it applies a 70% duty cycle to the coil, if the lock detection switch is locked it' 50%.

[Edit, sorry got interrupted]
3.X amps
to 2.0 amps

 

I can't really help much more than looking at the schematics because I have a non-locking 2WD truck, but... I'm gonna throw this out here anyways because it might be worth tossing the idea around.

We know the e-locker can be cantankerous even when attempting to actuate it in the Toyota-approved method of being in 4lo.

There are cable-lock conversions out there for other Toyota e-diffs.

My KISS (keep it simple, stupid) methodology would say that if faking out all the sensors proves to be too big of a problem, remove the electronic drive, convert to cable lock, and then simply put a little "simulator" module on the e-locker's harness, which could be a simple as a resistor shoved into the connector pins. (I don't know exactly what the harness looks for to determine if the diff is locked or unlocked)

Remove the computer from the loop entirely. The computer will be happy thinking you've never touched the e-locker, and you get full control that's far more reliable and robust.

It would require custom fab to get a lever into the cabin, yes, but I reckon that might potentally be an easier thing to fabricate than something that fakes out some 20-step ecu authentication with PWM signals.

 

So I don't know the most efficient way to produce the circuit, but I think we know enough to know the requirements for the circuit, and can make it.

The biggest thing I need to know right now, (if we stick with electrical operation), is do we need to disable ABS and TRAC when we enable anytime lock? (I don't know why Toyota did that, and I don't know if the 2nd gen did it or not). That would be super helpful answer to have right now.

 

A mechanical solution is not a bad idea, and needs to keep in the back of our head.

 

Nice. Thanks man

 

Apologies, actually read the entire thread this time .

I know this won't be popular from a reverse engineering standpoint, but at the outset I'd have to agree with those suggesting that this mod be "paired" with a 2lo mod.

I mean, if the truck can be fooled into thinking it's in 4Hi and then allow the change to low range, the locker should just following along normally (i guess?).

That would involve faking out more signals though, for example the Tcase status and limit switches plus the front diff status. hmmm

Note: I'm not even sure if it's mechanically possible to put this Tcase into low while it's in 2WD...

 

I'm working on a custom board with a solid state driver to replicate the behavior of the stock ECU. It'll sit in between the ecu and the diff. It just needs 12V power and a switch to operate.