VSC OFF switch install. (1 Viewer)

[Odyseuss]

This thread will describe how to install a switch and turn the VSC off on a 100 series that is equipped with VSC. I have performed this on my 01 LX470 with success, there may be differences between the models and years that I'm not aware of. I have found a few threads describing issues with VSC operation and questions about how to turn off the VSC, without any real solution presented. I though that it might help to post it here in its own thread for future reference. Do this at your own risk.


-Why would you want to turn off your VSC? There could be numerous reasons for this, and that's not really what this tread is about. I'll try and explain why I wanted to do it, but lets try to keep this thread focused on the HOW to do it and not derail in semantics. The VSC system was not installed on earlier 100 series that did not have ATRAC. Toyota equipped several various vehicles with TRAC OFF and VSC OFF switches from the factory, but not the 100. I wanted to be able to install that control and switch the system off.

So lets get down to how simple this really is. If you want to turn the VSC OFF, then you can lock the center differential. There is a signal wire that goes to the VSC ecu when the detection switch is closed and the wire is grounded. This mod manipulates that signal through the use of a switch to turn the VSC off when the center differential is unlocked.

I used a ON-OFF-ON SPDT switch. This allows me to complete the original connection with normal operation, an open/OFF position which turns off the TRAC and VSC, or a VSC off position which grounds the wire coming from the ECU.
I looked at the switches a bit and thought about using a VSC OFF labled switch, though the ones that I found did not seem like they would work right. The one that is available for the FJ Cruiser seems to be a momentary switch and aftermarket varieties seem to be ON-OFF only. If you find something else that works post it up.

Here are the diagrams.
On this page, you can see the VSC ecu and the Center diff lock detection switch circled. The wire that I switched is the Pink/Black pin 3 of connector A43.

This shows the area that I wired in the switch with the option to ground.

Below, you can find the location of the A43 connector and the ECU under the dash near the brake pedal.

Here are 2 more diagrams that show the VSC ECU and the A43 connector with the location of pin#3.

 

[Odyseuss]

Here is what my finished result looks like.

Any questions?

 

[Greenbean]

I'm liking this idea...

Good job on the details and instructions also.

How did you get VSC off in one pic and then both VSC and TRAC off in the other?

 

[Odyseuss]

I'm liking this idea...

Good job on the details and instructions also.

How did you get VSC off in one pic and then both VSC and TRAC off in the other?

I used a 3 position switch with an open/OFF position which turns off the TRAC and VSC, or a VSC off position which grounds the wire coming from the ECU.

 

[Greenbean]

Gotcha, the VSC off being like when your ctr diff is locked and the ECU turns it off.

10-4, Thanks.

 

[4WDarren]

Great write up, thanks! I've been reading some of the other threads on here regarding the matter, so it's nice to see someone figure it out!

I'm guessing there's no reason you couldn't just use a 2 position SPDT switch as well? I hadn't thought about the option of disabling ATRAC as well (and not sure if I'd really want to).

 

[elk]

It is good to know that you can turn the nannies off after all. Your rationale and solution are quite clean albeit I might have to look at the wiring a little more before digging into this modification myself.

 

[Odyseuss]

Great write up, thanks! I've been reading some of the other threads on here regarding the matter, so it's nice to see someone figure it out!

I'm guessing there's no reason you couldn't just use a 2 position SPDT switch as well? I hadn't thought about the option of disabling ATRAC as well (and not sure if I'd really want to).

Thanks. The TRAC off mode was not necessarily an intended result of this mod. It was an option that I observed while putting a plan into action, and I thought that it wouldn't hurt to have the extra option. I dont really have a need to turn the TRAC off at this time, and I don't really use that option. This mod does not turn off the Active TRAC in the VSC off position.

A 2 position on/on switch should work fine without the TRAC off option. Or you could just ground the wire and have VSC off all the time. I'm only grounding the lead from the ECU, so it doesn't affect the center diff lock circuit at all. The center diff still locks/unlocks as usual.

 

[LostAfrican]

Thank you! I need to do this. We have a canyon near Phoenix ( Salt River) where the VSC activates on the hair pins rsometimes and gives me a huge fright.

The VSC/TRAC light is a warning light. It is lit when there is a problem with either the TRAC and/or VSC. I don't think it means that the TRAC is off necessarily. It's probably lit because the input to the VSC ECU is floating - not pulled up or down. Without center diff lock activated the signal from the diff lock lamp is pulling the VSC input up.

 

[Odyseuss]

Thank you! I need to do this. We have a canyon near Phoenix ( Salt River) where the VSC activates on the hair pins rsometimes and gives me a huge fright.

The VSC/TRAC light is a warning light. It is lit when there is a problem with either the TRAC and/or VSC. I don't think it means that the TRAC is off necessarily. It's probably lit because the input to the VSC ECU is floating - not pulled up or down. Without center diff lock activated the signal from the diff lock lamp is pulling the VSC input up.

Thanks for the input. The VSC/TRAC light is a warning light that gets illuminated when the ECU detects that there is a problem/ not normal operation of the VSC or Active traction control system. It does indicate that the "Active traction control system is not operating, but there is no problem if you continue to drive."
Here are the associated pages of the owners manual. It also states that even if you use tires other than specified, the Vehicle skid control system may not operate properly.

 

[LostAfrican]

You are right Odysseus, when VSC/TRAC is lit, ATRAC is not working...bottom corner of p. 224.

Thanks to @Odyseuss for all of the info...you inspired me to get this done.
I decided to not have an option to disable the TRAC and just focused on VSC.

I over engineered my install a little by using a 5-pin relay so I could use a push button switch to disable/enable VSC. The relay also gives a satisfying click when VSC is disabled. I use the 5 pin relay to either connect the VSC ECU to the Center Diff Lock signal where the input to the VSC ECU is pulled up to 12 V for normal VSC operation. When the VSC button is pushed, it disconnects the ECU from the Center Diff Lock signal and connects it to ground, thus setting the ECU input to 0V and signaling to disable VSC. The dash/combi. meter is then lit by a different signal from the VSC ECU.

Here is a schematic (using pro-CAD tools as you can see ):

Here are some install pics:

This is a shot under the driver's side dash (LHD) showing the VSC ECU. The A43 connector is the second from the top and in my 2001 LX the wire is Pink with a Black stripe in position 3 (see diagrams from Odyseuss above). In the foreground with the yellow/blue/red/black/white is the relay. I used some double sided tape to stick the relay to the side of the ECU and on top of that little shelf on the left of it.

I chose to use the bolt on the left that attaches the metal shield behind drivers kick panel as my ground point. I stole switched battery power (12V) from an unused connector behind the switch panel to the left of the steering column where I placed the VSC switch. 12V is only used to activate the relay when it closes the connection between the common (connected to pin A43-3 on the ECU) to the ground on the relay.



Here is the switch panel. Switches are from ch4x4.com. They have a cool make your own custom switch tool online where you design your own, which is what I had to do to make a horizontal Light Bar switch.

Pictures of it operating. I also tested Center Diff Lock to make sure I didn't break anything.

Interestingly there must be a hysteresis filter on the ECU input because VSC/TRAC does not illuminate between when the relay moved from Normally Closed connected to the Center Diff Lock detect signal and Normally open Connected to ground. During the "inbetween" the ECU input would be floating. This is different behavior than seen in the OEM circuit with the Center Diff Lock detect switch, which starts pulling down the signal.

I think I might need to put a filter of that LED in the switch. Its pretty bright. I did not hook up the dash light/dimmer for the switch it self. Inside the switch there is an LED so its polarity specific, and the 100 series uses ground connected potentiometer to adjust the brightness.

It was a pretty easy job. Everything is easily accessible. Worst part is probably freeing up enough of the wire into the ECU and crimping some connectors on there. The button panel was very easy and there's power there that's easy to tap. Hope this helps you!

 

[Live to Ski]

Can anyone steer me to a link as to why this mod might be desirable?

 

[Odyseuss]

Can anyone steer me to a link as to why this mod might be desirable?

This topic has been widely debated on the internet and I'd rather not contribute to the debate here. I'll just say that the VSC system might not operate properly on vehicles with tires or suspensions that are not original equipment from the manufacturer. If the VSC is not operating properly, its function can cause some undesirable behaviors. This may include annoying beep noises, fuel cut, and braking that is not controlled by the driver at times when their operation is not intended. If you are unsure why this mod might be desirable, or you do not encounter these conditions, then this mod might not be a priority. If your vehicle is in good working condition and calibrated and you do encounter these behaviors, then this is a way to avoid them.

 

[uzj100]

And it is very hard to rally slide / drift the 100 with vsc. My 99 was so much fun. The 04 is very much under nanny control on gravel roads.

Thank you for the write up. I need to get this done to my 04.

 

[Live to Ski]

Odyseuss: Thanks for the "cliff note" rational.

I agree, probably above my pay grade as far as driving skills are concerned.

 

[WickedPickle]

Has anyone else done this hack and still seen no issues?

 

[YardPig]

@LostAfrican Do you have a link to the exact switch you used?

*** - Thanks figured it out on their site. Thanks for the write up.

 

[YardPig]

Has anyone else done this hack and still seen no issues?

Yes I wired as posted by @LostAfrican and it works perfectly. I used the relay and the same switch, makes for a factory looking install and I agree the relay click is a nice bonus.
Thanks again to OP @Odyseuss !

 

[aedgington]

So if I just wanted to disable it completely, I just need to ground A43?

Am I grounding the wire going into the harness (bottom) and taping off the wire going back up (top) ?

 

[Odyseuss]

So if I just wanted to disable it completely, I just need to ground A43?

Am I grounding the wire going into the harness (bottom) and taping off the wire going back up (top) ?

To disable the VSC, ground the wire coming from the A43 connector pin 3 shown in the first post. Cut and tape off the rest of the wire going to the detection switch if you do not want to be able to reconnect them. My second picture in the first post does not show wire being severed very well.