Trac/off Mod with factory switch

[Jixxer6]

I did this for a friend with an 03 V8. He showed me a link to the mod here and it was a bright idea but I wanted a cleaner look. 1st no running wires through the firewall, 2nd use the factory switch in the stock location. What makes this a little tricky is that the stock switch is only a momentary contact switch not an on/off switch like in the regular mod. What I decided to do was use a 2 position relay. When the relay is off the ground for the brake pressure switch flows un interrupted. When the button is pressed the relay opens and causes an open circuit briefly. The skid control module will recognize the problem and turn VSC off. When you turn off and restart the car the system resets and it's back to normal again. I used the factory harness plug for the VSC switch, It's there taped up and unused. It already has the ground in it and the wires for the bulb for the switch. All you need to do is cut the red wire and attach it to the ground side of the relay with another length of wire. The relay will require a key on power. I used the black wire on the plug pictured. It was unused behind the kick panel (where I'm hiding the relay). Now all that's left to do is cut the black wire on the connector closest to the firewall on the skid control module (pictured). Your going to connect those to the relay harness. On the relay harness you need to use the middle wire and one outside wire labeled 30 on the relay itself. I made a crude wiring diagram. Keep in mind ABS module is not correct its actually a skid control module. I'll try and make a better one.

 

[Jixxer6]

Here are the part numbers for the harness and relay.

 

[Jixxer6]

https://vimeo.com/149501026

 

[LOSTR4]

Very nice, clean install...I have a factory switch I converted it to push on and it stays pushed in, and push off the switch goes to original position...is there a way to use your clean install method that doesn't require wires from firewall to interior to function similarly but doesn't require turning off the vehicle to go back to "normal" mode?

 

[Jixxer6]

I don't think so. The only way I know how to do it is to creat a fault in the system since there is no signal built in to the skid control module. If you could get a V6 skid module to work in there I think it would be doable.

 

[Onefastchevy]

There is a way... Check this post, I plan to do this in the coming months...

http://www.toyota-4runner.org/engin...-grained-vsc-off-mod-v6-1gr-8.html#post997844

 

[SSt4r]

Is this to disable ABS or just VSC?

 

[Jixxer6]

It will disable abs,trac and VSC.

 

[BlackWorksInc]

Actually what it does is disable everything related to the braking system itself for the most part since you're basically disabling the Master Cylinder Pressure Sensor.

From the NCF (New Car Features) of the 2003 4Runner:

Fail-Safe

~In the event of a malfunction in the TRAC/A-TRAC and/or VSC, the skid control ECU prohibits the brake control (TRAC/A-TRAC and VSC) operation.

~In the event of a malfunction in the ABS and/or Brake Assist, the skid control ECU prohibits the brake control (ABS with EBD, Brake Assist, TRAC/A-TRAC, VSC, DAC, and HAC) operation.

~In the event of the malfunction in the EBD control, skid control ECU prohibits the EBD control. Thus, the brake and throttle control will be opened in the same condition as in condition without the brake control system (ABS with EBD, Brake Assist, TRAC/A-TRAC, VSC, DAC, and HAC).

The Master Cylinder Pressure switch monitors pressure for the accumulator and so on so disabling it means you're disabling one of the critical items the actuator/booster assembly needs to function and as a result it goes into the failsafe mode where EVERYTHING is disabled, not just ABS/VSC/TRAC. EBD (Enhanced Brake Distribution) and BA (Brake Assist) are very important features that get disabled as well, EBD among other things proportions braking force front to rear on demand (in place of an old non-variable proportioning valve), while BA is the emergency stop feature that makes the 4Runner stop on a dime when you slam on the brakes.

I've been playing around with the EWDs and Repair Manuals for the '03~'05 braking system to see if there's a way to disable a certain component to give a more controlled method of disabling the VSC/TRAC system.

 

[Jixxer6]

If it's only disabled for a second it should continue to send data once the button is released. In any case it's meant for off road ing or if your getting stuck in the snow not for around town driving.

 

[BlackWorksInc]

If it's only disabled for a second it should continue to send data once the button is released. In any case it's meant for off road ing or if your getting stuck in the snow not for around town driving.

If the DTC is set, the fail safe is active until the computer does it's sensor check (which would clear the DTC since those are single trip) some people like to use it on road as well. Like I said, it's what I found digging into what unplugging the sensor actually does.

I'm not saying don't do it, it works and I used it in the snow yesterday. But that's what I found out it does, so far. I'll post a bit more information when I learn more; but that line of research has taken a back seat to holiday responsibilities.

 

[03beater]

Actually what it does is disable everything related to the braking system itself for the most part since you're basically disabling the Master Cylinder Pressure Sensor.

From the NCF (New Car Features) of the 2003 4Runner:

Fail-Safe

~In the event of a malfunction in the TRAC/A-TRAC and/or VSC, the skid control ECU prohibits the brake control (TRAC/A-TRAC and VSC) operation.

~In the event of a malfunction in the ABS and/or Brake Assist, the skid control ECU prohibits the brake control (ABS with EBD, Brake Assist, TRAC/A-TRAC, VSC, DAC, and HAC) operation.

~In the event of the malfunction in the EBD control, skid control ECU prohibits the EBD control. Thus, the brake and throttle control will be opened in the same condition as in condition without the brake control system (ABS with EBD, Brake Assist, TRAC/A-TRAC, VSC, DAC, and HAC).

The Master Cylinder Pressure switch monitors pressure for the accumulator and so on so disabling it means you're disabling one of the critical items the actuator/booster assembly needs to function and as a result it goes into the failsafe mode where EVERYTHING is disabled, not just ABS/VSC/TRAC. EBD (Enhanced Brake Distribution) and BA (Brake Assist) are very important features that get disabled as well, EBD among other things proportions braking force front to rear on demand (in place of an old non-variable proportioning valve), while BA is the emergency stop feature that makes the 4Runner stop on a dime when you slam on the brakes.

I've been playing around with the EWDs and Repair Manuals for the '03~'05 braking system to see if there's a way to disable a certain component to give a more controlled method of disabling the VSC/TRAC system.

Ok so I have a million dollar question for you that only you seem to grasp the theory of. 2003 limited 4.7 with 228k miles. Anytime the pressure switch is unplugged or the red wire circuit is broken, all 3 lights come on the dash right? What causes none of my lights to come on when I unplug mine? Bad ABS module?

 

[BlackWorksInc]

Ok so I have a million dollar question for you that only you seem to grasp the theory of. 2003 limited 4.7 with 228k miles. Anytime the pressure switch is unplugged or the red wire circuit is broken, all 3 lights come on the dash right? What causes none of my lights to come on when I unplug mine? Bad ABS module?

Possibly a faulty pressure switch or a lag in the module detecting the broken circuit? It SHOULD be rather quick to notice, but then again I have seen modern vehicles do weird things despite what the books says.

Does it set a DTC after driving a while with it unplugged?