Ducky

Why thank.... wait a min.... are you being sarchastic?

aowRS

I think Lee should go pull that master cylinder connector and engage in some joyous snow donuts. That's the spirit!

Andreas

Ducky

Well I am already worried I'm going to have to modify your way of doing this mod, because I read further back that someone tried my way and it didnt do anything, but im not sure "how" he did it, since im stubborn I still have to try it for my own... all else fails I can use the switch to make a wireing harness for your way of doing it.

yabedude

I've have a PDF for the 2003 4Runner VSC wiring, but the file is too big to upload and I don't have a site to store and add a link. Can anyone help post the file? Send me a PM with your email address and I'll email it directly.

lee

never!

lee

yep, planning on doing just that tomorrow. unfortunately, ill be at work too late to feel like driving anywhere to do such things.

ill wake up early saturday and jet out there!

Ducky

Ok so it's Kinda Unconfirmed without a MM (Multimeter) but the switch was checked by someone who has it and it seems to be a Momentary switch...

"I guess it's a momentary switch, it pops right back out when pushed. Sorry,
no multimeter."

So I guess that means I should just get the OEM switch lol...

aowRS

Mr. Anas Platyrhynchos,
Any idea why that switch is so damn big? Momentary on/off or not, it's almost as if it has it's own circuit board inside.

Hmm.

I'll be quiet again.

Andreas

midiwall

I'll host it. mark@midiwall.com

midiwall

These PDFs are now online:
Good luck to you guys!

emplusten

mikNtx, did you try this in both 4WD and 2WD? I'm curious if the jumper works the way one would expect when the truck is in 2WD...

I've been studying the wiring diagrams trying to figure out signal/pin names. "CD" for V18 pin 24 indicates that the center differential is locked. BTW, I don't think that is the "line that tells the VSC that it's a 4WD" since it can be either on or off.

It seems like Andreas is definitely on to something. Great work!
Bob

mikNtx

bob,


i tried it in 2wd only. it acted as if it did nothing different. i got the familiar de-throttling and the skid indicator to light up. also checked my pin 26 switch connection several times as that connector is pretty deep. seperately, i'm also wondering if ABS is disabled in the 2wd model when their TRAC switch is activated (similar ecu theory).

- pin 24 -
if you have the diagnostic manual (vol1), check out both circuits on p. di-331 and di-347 on the vsc / center diff locking circuit. its interesting as i think these circuits are key in getting the thing to behave the way we want it. they both include the V18 pin 24 (CD).

for kicks, i decided to pull the master cyl sensor and it seemed to work as described earlier. on my 4r, the abs, vsc off, & vsctrac warning lights stayed ON even while plugging it back in (engine running). they went off and performed normally when i restarted the truck. i'll try it again over the weekend. from the manual, pulling the master cyl sensor fails the system in a higher level (ABS) failure mode (ref di-226) vs the VSC failure modes p. di-228. i'm also wondering if failing one of these circuits will get me the "VSC OFF" only fail safe mode. i would only like to see one failure indicator vs three.


mike

emplusten

Mike,
I don't have the diagnostic manual, and I don't think I saw those pages posted earlier. Can you scan them?

About the "Andy Mod", since the ABS, TRAC and VSC all use "Brake pressure" to function, it makes sense that not giving the VSC ECU master cylinder pressure info would disable the system. What doesn't make sense is that we can tell it that it has enough pressure for ABS, but not for VSC or Trac so that only those systems are . What are your thoughts on this?
Bob

aowRS

Bob & Mike,
Excellent sleuthing - I'm observing from the sidelines...

Mark - thanks for hosting the latest PDF files.

I agree that it would be nice to throw a switch and disable TRAC and VSC, yet retain ABS. But considering that the need to disable these systems is a temporary one (for most of us), I could live with having all three shut down at will. If I am in a slick, muddy situation off road, and need to sling as much mud as possible to extract myself, I could care less about ABS functionality.

I'm keeping my fingers crossed that the combined eagerness and knowledge on this thread will find out how to correctly integrate the factory switch. On the other hand, there are still three wires at the pressure sensor that could act as our last resort. Even if it means having to restart the truck in order to regain full functionality. As much as I loathe these two systems, VSC has certainly saved my hide from sliding into a few curbs on occasion. On a day to day basis, I would not even touch the switch. But if I know that I'll be in a situation that requires traditional wheel-spinnin' 4WD, I'd like to hit the switch. Restarting the truck after that would be a small price to pay for the freedom.

And the reimbursement offer still stands....

Andreas

aowRS

Bob,
Interestingly, someone a while back posted that when they pulled this sensor connector on their Sequoia, they retained ABS, yet were able to disable TRAC and VSC.

Andreas

mikNtx

after posting this, i now think that the detection switch D31 is more of a permission switch for the center diff lock switch C30 as C30 can only activate while in 4wd. now the feat is fooling the VSC ecu without activating the 4wd ecu. it still may not be possible yet as other 4wd detection switches feed into the vsc ecu. ultimately, it may be just easier to fail safe the vsc ecu another way listed on di-228. i need to get a code reader to find out what codes, if any, are being stored and see if they match our "fail" modes like the master cyl sensor.

driving with the master cyl sensor unplugged was fun. almost like driving my 2wd pickup w/ open diff w/ no de-throttling. no doubt i understand the liabilities of disabling VSC as the 4runner is top heavy and wants to roll more vs yaw on sticky surfaces.

on ABS being disabled, i would have to see it work on a slick surface while the master cyl sensor is unplugged. ABS indicator may be a warning and not a failure. the whole thing of putting these things in failure modes is that we do not know if another system is overcompensating.

sorry, i will not be able to upload the scans until monday as the scanner is at work. someone who has it electonically already might want to post them.


mike

aowRS

Mike,
I agree. To tell the truth, I did not try hard enough to get the ABS to kick in. For all we know, it may still be functional with the pressure sensor pulled. Even though the indicator is illuminated.

Andreas

yabedude

I don't understand why it's important to maintain ABS given TRAC and VSC are disabled.

Aren't both of those (disabled) systems the drivers for ABS or are we talking about when applying the brakes that it would be nice to have ABS kick in during a slippery situation -- such as on a steep downhill? I'm thinking that when I disable VSC, and eventually TRAC, I want out of the predicament I'm in and have little intention of touching the brakes.

About automatically reinstating TRAC functionality when the engine is cut ... a relay, or several, would seem to be the way to go. A simple push button that acts as a toggle (on or off) to a relay that is wired such that when the ignition is disabled, the relay tosses the latch(s) to enable TRAC again.

I'm not an electrician nor electronics expert, but these relay pages may help with some ideas:
http://www.the12volt.com/relays/page5.asp

In addition to the PDF wiring manuals for the 2003 4Runner, I have both VOL 1 and 2 repair manuals so will look through them later today searching for anything related to TRAC and VSC.

aowRS

Chris,
I don't think anyone is saying that they need to retain ABS if we are able to disable the two systems. It would just be nice to know that the regular ABS functionality is still retained when the switch is flipped.

Me, I just want to be able to shut this crap off when I deem it necessary. No CPU, circuit board, or any other electronic gizmo will ever be able to tell that I am about to plunge into a foot of mud or slushy snow. And that in order to get through this mess, I will need to mash the GO pedal to the floor.

Let us know if you find anything good in your service manuals.

Andreas

yabedude

Found something interesting in the manuals today regarding (2003) TRAC. It sure looks like something of importance. I sent a pdf off to Mark hoping he can host it again.

Excerpt: "This is the TRAC control main switch. When the TRAC OFF switch is pushed on, TRAC control goes off and the TRAC indicator lights up. Turn the ignition switch OFF, TRAC control surely comes on when the ignition switch turns ON next time."

It has a wiring diagram. The question I have is, where is the TRAC push button?!? Could it be an option that a dealer simply plugs in? Does anyone have the limited 4th gen? Is there a TRAC button to the right of the steering column? I have 3 spare plugs beside the factory DIFF LOCK button ... maybe the TRAC button goes there.