hillbilly

OK. After some snooping around and many inquires with Toyota, what I thought is true.

While trying to get closer to my hunting spot earlier this winter, I eventually got hung up on a steep logging trail covered in about 1' of snow. I discovered (like many of you) that I could NOT disable the Active TRAC system (traction control) on my '01 4Runner SR5 4x4, which actually killed my forward momentum causing me to get stuck. (Really ticked me off.)

So, while changing the oil one night, I snooped around a bit. I located a small relay box (fuse type box) over the passenger side wheel well. The cover markings notes a "TRC MTR" relay, which I thought might be the wheel spin monitor for the Active TRAC system.

Before pulling the relay, I contacted my local Toy dealer to find out if any other 'critical' services passed through that same relay. Turns out their techs had the same misconception most do. They said that 'locking the center diff. (VSC OFF) would disable both the Virtual Skid Control AND the Active TRAC system'. Strike one. The two are completely independent. But they did mention that it didn't appear as if any other 'critical' services passed through that relay.

So, I emailed Toy's customer support directly in hopes of getting some accurate info. Sadly enough, they too responded saying that 'locking the center diff. would turn off the Active TRAC and VSC system'. Strike two.

Long story short is, I pulled the relay and tried it. With the "TRC MTR" relay removed, I clawed through 16" of snow with the 4x4 engaged and snow flying passed the windows. Life was once again good.

The relay is a 12v, 4 post, relay. One leg is hot (red), one ground (white), and the other two (pink w/ black strip and yellow w/ black strip) probably run over to the ABS system and wheel spin solenoids. I hope to put a switch on the dash disable the Active TRAC so I don't have to remove the "TRC MTR" relay every time. Question is, which of the 4 legs do I connect the switch or I may even have to short two of the legs to get it to work??

The manual states the 4x2 models have a "TRAC OFF" switch on the dash to disable traction control. The manual also states my 4x4 has a "TRAC OFF" LED on the dash that will light up only if the Active TRAC automatically disables due to overheating from excessive use. It will automatically re-engage once an acceptable temp has been reached. This exactly why I want to be able to manually disable the Active TRAC, so that I DO NOT damage the ABS/brake systems when I know some amount of wheel spin is needed/unpreventable.

Ideally, I'd like to mount the "TRAC OFF" switch from the 4x2 models, on my 4x4 that will disable the Active TRAC system and turns on the "TRAC OFF" LED on the dash (next to the VSC OFF) so it'll remind that the Active TRAC is off.

Anyone have any thoughts on how to do this?? Better yet, anyone have a Electrical Service Manual for a '01 4Runner SR5 4x4 so that I might be able to get a little more info about the wire schematic related to the "TRC MTR" relay and how its wired/works??

I'm willing to bet this also applies to the Sequoia 4x4 as well. I took a quick peek at my father-in-law's '01 Sequoia SR5 4x4 while I was in last weekend, but wasn't able to locate the "TRC MTR" relay, but I understand they share similar 4x4 functions.

Thanks. Any help would be greatly appreciated.
HB

MO-Runner

Really don't know any info that would help, but would like to know how to do this myself. Am planning to get ARB lockers which should make this a non-issue, but would like to hear some input from others with more knowledge.

Good Times

hmmm interesting... maybe i'll look into that on my 03 4runner!

I would think that tapping the hot wire would do it no? Not sure but I'd have to take a deep look into this one as I wouldn't want to fry anything...

Citykid

Good work Hillbilly!!! That is exactly what I want to do also. I agree with you on all points (the switch inside, ability to keep the ABS working, tapping into the relay, stealerships being clueless.) I do not have the answers you need but can't wait to hear how it turns out. Please take pictures when you do this.

phong

Sounds to me like you need to get yourself a factory electrical wiring manual. I'd help you out, but they didn't add TRAC until 2001, and mine's a 2000. The best way to disable the relay would be to put a switch in series with the signal/trigger/activation line. Are there any numbers on the relay that can be used for identification? If there are, you might be able to look for the schematics online.

good luck.

hillbilly

Here's the details on the TRC MTR relay for my '01 4Runner SR5 4x4:

ABS (TRC) MTR
12V
89633-24010
056700-9820

It's a 4 post relay. From a passenger wheel well top view (looking down) the wiring is as follows:

Pink w/black stripe (small post on upper left of relay)

Yellow w/ black stripe (small post on upper right of relay)

White (large post on lower left of relay)

Red w/faint dashed silver stripe (large post on lower right of relay)

Thanks for any assist.

Darren

I'm not sure why you would want to disable the A-TRAC system as that is the only thing standing between you and conventional open diffs.

Please understand that it is only the VSC (Vehicle Skid Control) that controlls the throttling. I must have missed something in your analysis, but by locking the center diff, did that not resolve your initial frustration in that you lost momentum due to the engine being held back?

I cannot grasp why you would want to disable the TRAC system. Please enlighten me.


Edit: I have read and re-read closely what you've written, but I am still at a great loss of understanding. I know you or someone will chime in soon enough though.

hillbilly

I believe you're correct that only VSC controlling the engine throttle, but I'd have to test it again to be sure.

I do know this though. With the 4x4 engage (4Hi or Lo) and the center diff. lock (VSC off), Active TRAC engages the ABS on any wheel, ANYTIME it begins to spin.

I first discovered this going up a semi heavily snow covered (12")logging trail (saves packing the treestand/bow and other gear another ½ mile up the mountain). My first run at the trail failed partially due to Active TRAC and me backing off the throttle due to the excessive chatter of the ABS trying to keep the wheels from spinning.

Once I figuered out it was working as designed and that I hadn't forgotten to turn the VSC off (lock center diff.) or enable/disable something, I backed down the to the base of the trail and gave it another run.

Keep in mind this is probably a 7% grade with a near 90° switchback that leans a good bit to the left at the meat of the 90°.

With a good run from the base (nothing high speed just getting some momentum), the second attempt got me a bit further than the first, but the Active TRAC/ABS eventually killed my forward momentum enough to stop any useful progress (even without letting off the throttle), leaving me stuck on last third of the near 90° and eventually just kept slipping further and further down to the left (inside of the turn) the more I tried to get out since I could no longer go forward. No matter what I tried, I could no longer gain any forward momentum because the ABS kept the wheel from slipping. So I backed into the woods and squirmed my way out to the base and hiked up like I always had before I bought a 4Runner.

I verified this again a few weeks later on a flat logging trail with approx. 12"-14" of crusted snow that was rutted out by serveral other 4x4's earlier in the week. Everything was going when I was parallel with the ruts. Then I tried to turn around to head back and it all few apart. Once I was perpendicular to the ruts, and the wheels slipped into the ruts the other 4x4's created, the Active TRAC made it real tough to get out because it kept the wheels from spinning (even a little). Without some amount of free spin the wheels just can't 'claw' out of crusted snow. I eventually rocked it out, but the ABS was chattering like hell the entire time.

I get into these kind situations pretty frequently because of the terrain of where I bowhunt. The reason I want to be able to manually disable the Active TRAC is to prevent any damage to the ABS/brake system (& pads) when I know I'm going to be getting into places where some wheel spinning is unpreventable.

The manual states the Active TRAC will automatically disable itself when excessively used if it senses an overheating condition within the ABS system. I want to disable it before it overheats, because I'm will to bet years of excessive/prolonged activation of the Active TRAC will evetually cause problems somewhere. I'm also willing to bet any travel on loose semi deep sand would real frustrating with this Active TRAC system too.

Curt

Darren,
I am pretty sure the Sequoia is a bit different than the 4 runner because I too have been caught in the position of not being able to get enough wheel spin to get out of a bad situation (NO MATTER WHAT I DID). The only way for me to disable traction control is to be in 4L 1st gear forward. If I need to rock backwards as soon as I place it in reverse I loose diff lock and traction control screws me.

Traction control is useless in snow situations if I can not get any higher speed wheel spin in both forward and reverse open diffs or not. Right now I can get all 4 wheels to spin very slow all day long but i can't get the truck to move without the wheel spin. It is ugly, I had a ML430 and it had an option to disable and I never had any problems even though the diffs became open. Just my experience

Darren

Hmmm. Well, that's kind of the scenario I was thinking you were meaning but wasn't real sure.

I had a chance to give it a real good workout the past 2 days here ( ) and it worked the same on snow as it does in an off-road environment and I have no problems with how the system handled it. All 4 tires spun for quite a bit before the TRAC system kicked in. I understand that sometimes wheel spin is desired in snow and I can kind of imagine that in a slightly different situation, braking a wheel could cause some momentum loss. I have yet to run into that however which is why I was questioning this.

hillbilly

What do you consider 'quite a bit' when you were referring to the wheels spinning before the Active TRAC activated? Were you in 4Hi or 4Lo??

I've tried both 4Hi and Lo and the Active TRAC (ABS) starts chattering almost immediately if the wheels start slipping.

After I removed the TRC MTR relay I was able to nail it and the ABS never kicked in.

hillbilly

Complete agree with you comment Curt. The only problem is my rig is an '01 4Runner SR5 4x4 too. My father-in-law has a '01 Sequoia SR5 and after looking at his manual it appears both the '01 Sequoia/4Runner function identically as far as the VSC/Active TRAC systems are concerned. Neither can be disabled.

Darren

I was in 4-low, 1st gear. As for how much "quite a bit" is? I don't know, in certain situations where it was a flat surface, it was at least a few seconds, maybe more, and the RPM's were really up there. That is quite a sufficient amount of time though if you're going to move at all. This was in snow that I was plowing with my TJM (deep!). In reverse, I'd see snow being kicked up from both sides above the windows.

It was in deeply rutted spots where the system kicked in the most and right away at that, but on flat surfaces it would spin before activating. Again, I have zero complaints with what I faced.

It's the VSC that I would love to live without.

Good Times

not sure if this will help any but....

was at the stealers waiting for my 4runner... anyway long story short..

i was looking at the 03 4runner (2wd versions) and on their dash to the left of the steering wheel, they had a button that said "trac off".

Now I'm not sure if I read this correctly but if the 2wd's can disable their trac then there's gotta be a way to disable the 4wd's right?

guess i gotta start looking into the diff wiring setups for the 2wd and 4wd to compare...

just thought I'd inform ya so if you figure out a way this might help you.

Lance

hillbilly

My thoughts exactly! After reading the manual and discovering that the '01/'02 2WD's had a "TRAC OFF" button.... I knew there was a possibility I could add this to my 4WD.

'01/'02 2WD Sequoia's also have this ability, but the 4WD's don't. From what I've read/seen I suspected the '03's also fell into this category. Sad.

Seems as if Toy's trying to make it's newest generation 4WD SUV's just another kid kart. So much for that renowned off-road reputation they've established...

Let me know what you find... I'll do the same.

Citykid

Well, here's a question. Why the 2x4's and not the 4x4's? What would be the reason not to give the 4x4's this option?

PXL

New to the Forum and a seriouis 02 4Runner wheeler, I wanted to add to the discussion... I have been curious about how to disable the VSC as well. When in 4 Wheel low with the diff lok activated, (the VSC light comes on and the VSC should be deactivated) the ABS motor still works in some situations for some reason. I will try the advice and pull the "TRC MTR" relay, I always wondered about it because I did not want to set any fault codes after removing it.

The problem that I have with the whole system (01 and 02 4Runners) is that in 2 HI mode (regular street driving), I want to spin the rear tires at will. As you all know, when the rear tires spin for just a split second the ABS kicks in "and" the engine timing is retarded to the point where you basically have no power- period. I have a trouble ticket on file with Toyota at this time to formally documet a potential hazzard. Here is the reason... I was pulling away from a stop sign one day and the rear tires spun for a second in some gravel, meanwhile a vehicle blew the stop sign coming from the other direction... in the split second the rear tires began to spin and the engine timing was retarded (opposite of being advanced) I sat helpless in the intersection... a potential accident waiting to happen. So someone mentioned earlier, why did Toyota not install the "TRC OFF" switch on 4x4 versions?

Another reason to disable this so called saftey feature is you loose all the potential to play in the sand, snow, or creek bed... when you want to slide the vehicle on purpose the warning buzzer comes on and the ABS is activated (pulsing the brakes to straighten out the vehilce) which in my opionon makes the vehicle feel unnatural.

ARB's front and rear, 3" Revtek lift/drop kit, 285x75x16 Yokahama Geolander ATplus2's, sliddes, front and rear bumpers, deck plate mod, extended axle breathers, extended trac bar...

Thanks, Pete

monstermazda

[IMG]file:///C:/DOCUME%7E1/User/LOCALS%7E1/Temp/moz-screenshot.png[/IMG]try this

monstermazda

looks like the trac off switch from the 4x2 can be installed on the 4x4. the first pic in this post has the switch in it.

monstermazda

ok i just climbed under the dash of my friends 01 4runner and looked at the trac computer. theres 4 connectors from the bottom its the 3rd 1 up (white connector between 2 black connectors). pin 26 is empty. according to the diagrams i posted, connecting it to ground should in theory do the same as the trac off switch, will repost after trying.