VSC Off mod complete...

[jgmx893]

Well I decided to go for the vsc off mod via grounding the wire that goes from the Center Diff computer to the 4wd computer. It seems to work fine, but is working slightly different from what other peoples' results have been.
I actually do not get a CDL light on the dash, and instead get a "vsc off" symbol, another vsc symbol, and a "vsc/trac" symbol. I also have to turn off the truck and restart it with the switch open for the lights to go off. I'm wondering if this difference is because I put a switch with an led in? When I was testing the mod just touching the wire to a ground I got the "vsc off" light and the CDL light, that was it....
Any opinions?
By the way, my switch is a 3 prong, One is for the led power and is what I have my tapped wire going into. The other is for a "relay/application". The 3rd prong is my ground.

 

[470SNC]

Can you post a link to this mod tutorial, the vsc off/trac off lights are normal, and yes you need to restart to reset the light, thats all normal

 

[robtmc]

This is indeed quite different than what I get. The dash symbology I get is the same as when the CDL lock is activated in 4WD. Can you sketch out the circuitry you used?

You are simply grounding Pin #27 of the VSC ECU? I tapped into it down on the kick panel rather than in the engine compartment. Recently re-did how I acitvate it after being displeased with using the CDL button to turn it off. Too tricky.

Now successive VSC off presses cycle it fine, and it still shuts off with the ignition.

 

[jgmx893]

what mine looks like

This is indeed quite different than what I get. The dash symbology I get is the same as when the CDL lock is activated in 4WD. Can you sketch out the circuitry you used?

You are simply grounding Pin #27 of the VSC ECU? I tapped into it down on the kick panel rather than in the engine compartment. Recently re-did how I acitvate it after being displeased with using the CDL button to turn it off. Too tricky.

Now successive VSC off presses cycle it fine, and it still shuts off with the ignition.

I honestly don't know enough about circuitry/electronics to make a worthwhile sketch, so I'll reference these pictures:
This shows the wire that I tapped into/the wire that's being grounded. It is red with a blue-ish stripe. I tapped into it right before the 4wd ecu, right where the yellow text box is


Then I put in a rocker switch w/led in it. The wiring diagram they sent me with the switch was essentially this withough #1


So then I have the tapped wire going to pin 2 on the switch and grounding through pin 7. This way it passes through the led and illuminates it on its way to ground. I'm thinking the led has to be the reason my mod is acting differently...but yet the ecu isn't fried or anything or malfunctioning (to my knowledge). And I don't know how the led would make a difference anyway

 

[robtmc]

That is the same signal line I am using to fool the VSC ECU.

What is possibly happening is you are not pulling it fully to ground. If you have a multimeter, measure the voltage when switched.

Dunno how low the Toyota ECU needs to "see" the voltage go to interpret it as grounded.

You can also just temporarily bypass the LED to ground things and see if it acts the same.

 

[jgmx893]

That is the same signal line I am using to fool the VSC ECU.

What is possibly happening is you are not pulling it fully to ground. If you have a multimeter, measure the voltage when switched.

Dunno how low the Toyota ECU needs to "see" the voltage go to interpret it as grounded.

You can also just temporarily bypass the LED to ground things and see if it acts the same.

Yea I think that's going to be my plan is to temporarily bypass things and see what happens. When I was first testing it by doing just that, it was acting the way it should as if the center diff was locked. So if that's the issue I'll just put in a simple toggle switch w/no led. Thanks for the input though, it's definitely a strange issue.

 

[SSt4r]

If it's running through the switch AND through the LED seperatly to ground, then it should be seeing plenty of "ground". My concern would be that there might be more (although very slight) DRAW through that circuit because of the LED. Not sure I'd want to risk that.
Probably no need for the LED in the switch as there are plenty of warning lights on in the dash to remind you it's activated!

 

[robtmc]

I actually do not get a CDL light on the dash, and instead get a "vsc off" symbol, another vsc symbol, and a "vsc/trac" symbol. I also have to turn off the truck and restart it with the switch open for the lights to go off.

After re-reading your post and looking at the dask lights, it sort of looks like the VSC ECU is going into a fault mode like the full no "VSC/TRAC/etc" mod does. That is the one that interrupts the brake level sensor line.

The fact that you have to turn the engine off and restart is what tipped me off. Possibly the non-zero voltage at the VSC ECU trips the fault mode?

When done right, it goes on and off just fine with the engine running. Then again, what you have does the job, and possibly allows switching 4WD modes, which the VSC only mod does not.

Have you tried switching modes? You might have stumbled on another method of doing the complet VSC/TRAC defeat that does not require any wires running in from the engine compartment.

 

[jgmx893]

After re-reading your post and looking at the dask lights, it sort of looks like the VSC ECU is going into a fault mode like the full no "VSC/TRAC/etc" mod does. That is the one that interrupts the brake level sensor line.

The fact that you have to turn the engine off and restart is what tipped me off. Possibly the non-zero voltage at the VSC ECU trips the fault mode?

When done right, it goes on and off just fine with the engine running. Then again, what you have does the job, and possibly allows switching 4WD modes, which the VSC only mod does not.

Have you tried switching modes? You might have stumbled on another method of doing the complet VSC/TRAC defeat that does not require any wires running in from the engine compartment.

Haven't tried switching modes and don't really want to. I actually tested it by running it straight to ground today and figured out it was in fact the led, probably leading to non-zero voltage going into the ECU. So I just modded the switch to not go through the led, and now it works fine, like it should. I would assume it would have been able to change modes the way it was though. What would happen if I tried to change modes now that it is working fine? Would it just not want to change modes or would something worse happen? Also I'm assuming to change modes I just open the switch, switch (for example into 4low) and then close the switch back?

 

[robtmc]

Haven't tried switching modes and don't really want to. I actually tested it by running it straight to ground today and figured out it was in fact the led, probably leading to non-zero voltage going into the ECU. So I just modded the switch to not go through the led, and now it works fine, like it should. I would assume it would have been able to change modes the way it was though.

Was curious if it was in the same state as when the plug is pulled or wire interrupted in the engine bay to completely disable VSC/TRAC.

What would happen if I tried to change modes now that it is working fine? Would it just not want to change modes or would something worse happen? Also I'm assuming to change modes I just open the switch, switch (for example into 4low) and then close the switch back?

If you are in 4Hi, it will not go into 4Lo unless you switch it off first. It will go into 2Hi, but will keep blinking on the dash. This was what CJ3Flyr figured out to get VSC off in 2WD. So yeah, have to switch off to change modes or it just sits there. Since the change is fast, not a big deal.

This need to quickly turn it on and off is why I junked my first iteration of relay control that used the CDL lock switch as the off button..