ABS/Traction Control Kill Switch Help

Background: I have a 2016 TRD Sport (LSD, no locker, 3rd gen) with a fresh fj transfer case in it. Lights on the dash are going off, which was to be expected. My plan is to follow @BigWhiteTRD 's guidelines on spoofing the ECU into thinking its in 2Hi all the time (resistors are in and ready to be soldered).

Before I do this though, I would like to wire a kill switch for the ABS and Traction Control. In 4Lo, the ECU will automatically do this for us but because my ECU will still think it's in 2wd then I have to do this. Does any have any tips on where or how to wire this? I have a basic understanding of wiring components and how to connect (spline, solder, heat shrink etc) them but not exactly what I'm looking for. Thanks for the help.

PS: @bravinci what did you do for this? Did you just leave your dash lights going off?

 

I just reconnected my tcase actuator in the cab... that way the lights don't constantly go off - but I'm waiting on lapoltba and the 2lm harness so I can modify it to BigWhiteTRD's guide for the 4WD ECU Spoofer. That way I don't have to hack into my stock harness and I can modify it if needed.

https://www.tacomaworld.com/threads...-2wd-low-range-for-the-3rd-gen-tacoma.614743/

 

There is no elegant solution that I found (that I am capable of doing, like canbus spoofing) that met all my desires.... (like not throwing codes, etc).... There are certainly ways to do it that throw codes, but no method that didnt throw codes that I found before giving up.

In the end, my best suggestion is to use my original FJswap ECU spoofer schematic. (when you do it that way, the ECU will think you are in 4lo when you activate the spoof.)

The BIG drawback of that system. to activate the spoof, you shut off the truck, activate the spoof switch, then restart the truck....

That make sense?

(somebody claimed that their dealer permanently disabled it in techstream if I recall correctly. I Can search for that thread if you want. I couldnt find how they would do that in Techstream, but thats maybe a possibility if you want it permanently gone without codes.... MAYBE)

 

I do plan on playing around with a microcontroller once I get the spoofer working. At least then I'll have something to work off of. I've been youtubing / Googling a bit and it kinda looks like a fun project. It would be neat to remove the spoofer switch altogether, and just use the factory dial to control the ECU, and have it accept whatever mode you tell it it's in with no codes or lights.

 

Wait... Yall keep saying the "Lights go Off".... Were they on to begin with?

 

The truck looses it's mind when you unplug the transfer case actuator or ADD. It reads the resistance from the electric motors, and when that resistance isn't there the truck will throw some codes - "lights go off".

 

It would be a fun project. I think I could probably do it with a raspberry pi... I DONT think i could do it reliably though....
Meanwhile I am working to put 32 solar panels on my (garage) roof... what dumbass thought this was a good idea in the summer....

 

Well BOTH actuators are disconnected for me because I have a plug and play harness to the ADD to manually tell the driveshaft when to connect to the differential so reconnecting the old case actuator isn't really an option

It does make sense although I think I would rather just have a switch to manually turn off abs/Traction Control, trying to take computers out as much as possible. So I'm doing what we talked about with the 2 resistors and just need to figure our the abs/Traction Control Kill Switch, if you have any ideas on that

I have very limited experience with Arduinos and Raspberry Pi's but not even close to the extent of actually trying to develop my own code and wiring job. It's more of an understanding with limited hands on and I never want to get back into them lol so back to the kill switch for the mechanical guy

 

The 2Lo harness advantage that @bravinci mentioned is to avoid hacking into the stock truck (tiny wires) harness. He wont be actually using 2lo function from the harness... Basically that 2lo harness is pretty much cheaper than trying to buy and assemble the connectors yourself (the ECU attachment connectors).

I tried hard to disable ABS/Traction control, as part of anytime lock mod work I was contributing to. There were NO good ways to kill it that I found. The best way I found is given in this post below, however let me be very clear, I never tried fully to implement ABS kill so it isnt fully tested. I didnt like the truck behavior and the possible failure risks with this possible (minimally tested) mod. I tried disconnecting quite a few pins and checking the truck behavior, but I didnt check every one. I dont think we will find a reasonable mechanical way to disable ABS without throwing codes, I think the engineers were too careful to avoid simple failure modes that take out ABS.
https://www.tacomaworld.com/threads...-gen-development.537810/page-10#post-19104244

 

Well if you couldn't find it, I can almost guarantee I won't find it.. BUT you said "without throwing codes" so that makes me question: is there a way to kill ABS/Traction Control WITH throwing codes? Almost like adding a switch in line of the wires going into the ECU?

So overall end goal for this idea: truck thinks I'm in 2Hi at all times. I flip a switch, it throws codes at me and would cut off signals going to the ECU, but those codes disable abs and traction control. The "2wd-4wd change error" and "check abs" codes disable both I believe. It's not entirely elegant but still somewhat gives the driver control back

 

Yeah, you can cut about any 1 in about 40 wires will do it (throw a code and disable abs, traction control). Mainly any wire going into the skid control ECU are the ones that will kill abs and trac. One of the power wires to the skid ecu is the best I found. But per my memory i had to turn truck off and on to clear the fault, and it will be recorded in the ECU as an event (if not a current MIL light)

 

So I'll be following the diagram you sent to spoof the 4wd ecu into thinking its always in 2Hi (pictured below). Couldnt I just wire in a switch to any one of these connections I'll be soldering (the ones needing the resistors) to cut the signal to the ECU to make it come up with the errors pictured above? And these errors will cut off abs/trac control. Instead of messing with another ECU, just all occurring with the same sets of wires. So (assuming red wire is power) I could just solder a switch into that line and cut the power, forcing the truck back into the dash lights. Does that make sense?

 

It is certainly possible. You will have to give it a shot.
(thats how I got 2Lo working is just trying.) The repair manual doesnt appear to have enough data on the failsafes. I didnt recall many of the 4wd ecu failsafes causing ABS/TRAC failures, but if the ECU doesnt know its in 4lo, it might...

Reverse engineer that baby.

 

Well I suppose it's a maybe! Lol
I'll try it hopefully this weekend and will get back with you! I'll need you to confirm the wires I need to cut anyways, I still need to grease the connections and vacuum seal the harnesses.. you could say I've been slacking because the wiring has always been my least favorite part