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Anonymous
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Is there any way to disable ABS?
      #261686 - 12/16/00 08:32 AM

With winter setting in, I definitely realize how much I hate ABS brakes. I'm certainly not the only one. However, I know that they helped save my butt (and my bumper) a couple of times. But like I said in an earlier post, I have P265 winter tires, which is too wide. As a result, whenever there's deep snow (or worse yet, ice!!), ABS kicks in the minute I step on the brake pedal. It's very annoying.

Also, I've only had ABS since february 1998 when I bought my Pathfinder. I have to say that the Toyota system is quite a bit more subtle. But I drove 7 years without it and frankly, it is sometimes better to pump the brake pedal to get the «lock-unlock» combination manually to effectively come to a stop. There were times when I had to resort to the parking brake to stop the Pathfinder, and the Runner promises to be even worse...

So, I've been wanting for a while to build a switch that I would connect to the ABS fuse to have the freedom to turn it off manually if and when I want to. Has anybody done that? Is there another key component of the car connected to the ABS fuse that shouldn't be turned off? Does anybody know how to do such a mod?

Some of you will probably tell me that I shouldn't do that and that ABS brakes are there for my own safety, but I narrowly escaped a few accidents because of them. They would also be on 98% of the time, but in some snowy conditions, the snow packed in the tread of the tires is more effective if the tires will lock and act as a plow than if they're not allowed to.

So, if the wizards of 4Runner mods on this board wnat to help me, I'll gladly make a full report on the subject!

------------------
Hugo Lafrenière
'99 SR5 V6 5sp


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Anonymous
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Re: Is there any way to disable ABS?
      #261687 - 12/16/00 09:25 AM

Pull the fuse.
That is the easiest way to defeat ABS , when you want ABS put the fuse back in .
Thats what I have done with my race car.
Works well , cheap and simple.

Robert VanLane
Aomori Japan

PS When you pull or replace the fuse, always stop the car first. The CPU has to reset it self.

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little_joe
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Reged: 01/01/00
Posts: 10859
Loc: Holly Springs, North Cackalack...
Re: Is there any way to disable ABS?
      #261688 - 12/17/00 12:53 AM

Hugo, vehicle electronics are akin to the Sanskrit language to me. But FWIW the ABS sensor is conveniently located on top of the rear differential, with the wiring running up the frame rail.

I suggest this as a way to splice into the wiring and add a switch to control the current. I don't know how to do it, I'm just suggesting this since pulling a fuse doesn't seem to be the solution you're seeking. Perhaps someone will have something better to offer......

------------------
Joe Micciche
Joe@4x4Wire.com

'94 Toyota SR5 V6 Xcab, 33" MT's, locked and dented.


--------------------
4x4Wire's Toyota Section
1995 FZJ80 LandCruiser - 3 locking diffs, +200k mi, JD HIR's, 285/75R16 Nitto TG's
Olde North State Cruisers


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Anonymous
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Re: Is there any way to disable ABS?
      #261689 - 12/16/00 03:40 PM

quote:
Originally posted by Roger:
Just wait..you say your ABS kicks in with winter tires? I have not had my ABS kick in once this winter with the winter tires. it's not the 265 that's too wide or whatever..it's your tires...or you were going too fast for any size tire!


Well Roger, did you have any real snow this year? If you're from Canada (where, by the way?), you probably have. Anyway, even if I'm not going fast, I don't have to hit the brakes hard for the ABS to kick in. On packed snow, it's okay I guess, but on «loose», fresh snow, and especially if it's like 3 or more inches deep, forget it : non-stop ABS. You're running Winter Duelers right? And for summer : size and brand?

Thanks for the input guys. I was actually thinking of inserting two wires, one in the socket for each «end» of the fuse, and connect that to a switch. Would it work? Dunno...

------------------
Hugo Lafrenière
'99 SR5 V6 5sp


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Anonymous
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Re: Is there any way to disable ABS?
      #261690 - 12/16/00 03:42 PM

Okay Hugo, I just wrestled with the same question--while doing the wiring for the upcoming electric locker, I had the option of making an ABS defeat switch. FYI, the ABS has several modes: While in 4wd, it follows a different braking pattern. There is also a deceleration sensor (that is active in 4wd), so that it can tell whether or not the vehicle is on a slick surface (if the ABS is activating and the vehicle is not slowing down, it slows the pulsating action so that the wheels will remain locked for longer periods of time). Are you in 4wd when you are having probs with the ABS?
That would be first recommendation if you are unhappy with the ABS--try seeing how it does with 4wd active.
I think there are a couple of ways to defeat the ABS with a switch. If you have the rear electric locking differential, there should be a really easy way. (Mine unfortunately did not come with the rear diff lock, so the ABS ECU is a different part number--which apparently doesn't deactivate when wired to the proper pin). If you have the diff lock, disabling the ABS involves splicing into a wire running into the ABS ECU (located behind panel in passenger footwell) and feeding it 12V--this is the same circuit that the rear diff lock switch activates to disable ABS while locked. If you want to do this, let me know and I'll go look up the specifics in my wiring diagram.

------------------
Paul
99 4Runner SR5 4wd
5-speed
Electric Rear Locker Retrofit in Progress


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Anonymous
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Re: Is there any way to disable ABS?
      #261691 - 12/16/00 04:48 PM

quote:
Originally posted by RobJapan1:
PS When you pull or replace the fuse, always stop the car first. The CPU has to reset it self.

Thanks Robert! When you say «stop the car», I'm assuming you mean turn it off completely right?

------------------
Hugo Lafrenière
'99 SR5 V6 5sp


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Anonymous
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Re: Is there any way to disable ABS?
      #261692 - 12/16/00 10:06 PM

Yes that`s right.
When the car is turned on , it checks the ABS, and if it is off, the light will show on the dash.

If you don`t believe me , it is real simple to test out.

Robert VanLane

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Jeff the marmot
Trailriding Forum Moderator


Reged: 02/13/00
Posts: 4679
Loc: Thornton, Colorado
Re: Is there any way to disable ABS?
      #261693 - 12/17/00 03:43 AM

PaulC -- that's a great explanation for this.

I looked into disabling the ABS a while back but I'm still in the daydreaming mode for this mod. After ABS engages in 2WD mode, I don't like how sensitive it is -- it doesn't want to get out of modulating the brakes whether it should continue to or not. I think this can easily extend the braking distance while on-road. It seems that if I momentarily let off the brakes and then get on the brakes again, that I can stop ABS from modulating and ultimately stop sooner. However, I'm quite happy with the ABS performance so far while in 4WD.

IMHO, as with many vehicle makes, the hazard light location is a stupid location for a button that's so rarely used and yet in the most prominent location on the dash. Ideally, I'd like to rewire the hazard light switch to a new switch somewhere else, and then use that pushbutton switch for a panic ABS disable button. Like Paul said, since I have the electric locker, any custom ABS disabling circuitry should utilize the wire that goes to the ABS ECU to gracefully disable the ABS anytime the 4Runner is on or even moving.

There's a yellow with blue stripe wire that comes from the rear diff locker detection sensor and Y's off to a few places, including the diff lock light on the dash and then the ABS ECU input EXI2 (also labelled 4 - pin 4 maybe?). This is what Paul says needs 12V applied to it. So can we wire this thing so that it maintains the existing functionality, plus you simply drop 12V to that side of the sensor via a switch? I think so, but I want to review the wiring more before I just go for it.

I was originally thinking I'd add a switch and/or relay in-line with the ABS actuator fuse, but it's rated at 60 amps. I realize there's a huge safety factor in there, but still it would be hard to find anything rated for 60A. I've looked over the factory service manual for this and seen that there's 3 additional 10A fuses that go to various portions of the ABS system and each of these still terminates at the ABS ECU so it knows when all's well or if there's a power problem. Those 3 other fuses include lots of other things, such as dash lights, and power to many non-ABS items, so they all need to keep power to them.

I know people in a variety of other vehicles just remove the ABS actuator fuse when the engine is turned off. Then to re-enable it, they replace the fuse when the engine's off, restart the engine and ABS works again. But I would love to enable/disable it at any time from inside.
Hope this helps someone to take this to the next step. I'll probably get to it eventually.
Jeff

--------------------
Jeff
2000 4Runner SR5, supercharger, rear e-locker, ARB front locker, 285/75R16 MT/R's, custom bumpers & skids
2007 Tacoma double cab 4x4 - stock


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Anonymous
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Re: Is there any way to disable ABS?
      #261694 - 12/17/00 05:32 AM

Even if you have a switch ,you still have to turn the car off and start it up again for the ABS to turn on or off.

Robert VanLane

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Anonymous
Unregistered




Re: Is there any way to disable ABS?
      #261695 - 12/17/00 05:44 AM

This is some of the info I collected from the rally list I belong to.


1)
A defeat switch simply interrupts a signal (circuit) somewhere in the ABS's
electronics. As Ivan pointed out, you may be able to remove the fuse (or
relay). On my car (a 91 Eagle Talon (same as Mitsubishi Eclipse)) an 80
amp fuse protects the main circuit and it is bolted in place. It did not
seem practical to remove this fuse each time I wanted to defeat my ABS.

After a little searching, I found a pair of little wires (18 gauge) that
lead into the HCU. I snipped a wire and connected a wire to each loose
end. My two wires lead to a switch on the dash. By opening the circuit
(flip of the switch) the ABS detects a fault and disables itself. The only
problem with this is that the system can only be reactivated by cycling the
key from off to on again. Simply flipping the defeat switch back to the ON
position does not restore the ABS.

2)
I have not removed it, but I have installed a defeat switch. There are
some cases where I do want ABS functioning (wet pavement, for example).

Completely removing the ABS from your vehicle can be done and it can
simplify your brake system. Just be prepared to do a lot of tube routing
(bending, flaring, etc.). Most vehicles that do have ABS tend to have
rather complex routing to begin with. Make sure you look at this carefully
before you undertake such a task. Also keep in mind that your brake system
is one of your most important safety features (just like your helmet and
harnesses). DO NOT take on a job like this without fully understanding
this.


I hope this helps somebody.

Robert VanLane
Aomori Japan



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Anonymous
Unregistered




Re: Is there any way to disable ABS?
      #261696 - 12/17/00 06:20 AM

Thanks a lot Paul. I don't have the locker and mine is also a 5-Speed, and also a 99. If it's green, gee, maybe my keys will start your truck! If you have the V6, wiring should be the same. I'd appreciate if you could look into your wiring diagrams and e-mail me on that. Where did you get that info on how ABS works whether or not 4wd is engaged?

------------------
Hugo Lafrenière
'99 SR5 V6 5sp


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Anonymous
Unregistered




Re: Is there any way to disable ABS?
      #261697 - 12/17/00 06:28 AM

quote:
Originally posted by RobJapan1:
(1) Even if you have a switch ,you still have to turn the car off and start it up again for the ABS to turn on or off.

(2) The only problem with this is that the system can only be reactivated by cycling the
key from off to on again. Simply flipping the defeat switch back to the ON
position does not restore the ABS.


As for number 1, I'll check it out. I have to admit I'm a little skeptical, because removing the fuse, even while the car is running, should disable ABS since no electricity could run in its circuits. Anyway, I'll look into that.

And for number 2, maybe there's some logic there. Does this apply, from your knowledge, to all cars, or it happens to be the case only with the rally cars discussed on the forum this quote was taken from?

I'm really looking for a on-off switch that would enable me to switch ABS off in my street, keep moving, and switching back on when getting on the highway. At least, I'm not the only one daydreaming about this .

------------------
Hugo Lafrenière
'99 SR5 V6 5sp


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Anonymous
Unregistered




Re: Is there any way to disable ABS?
      #261698 - 12/17/00 06:54 AM

Yes that on/off switch is what I wanted too.
The shop that does all the prep work on my Rally car just pulled the ABS fuse and when I asked him why not make a switch, he laughed and said it`s not worth the time to wire it up.

My electronics skills are limited to a High School class, I took along time ago.

If somebody has more info on ABS I am definitely interested .

Robert VanLane

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Anonymous
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Re: Is there any way to disable ABS?
      #261699 - 12/17/00 07:03 AM

Originally posted by Roger:
I read somewhere that the union workers protested and didn't clear the roads. Could it be true they also don't salt the roads?!

Yes, it's true. They refused to do overtime and drove on the streets with their plows up. Jerks...

Perhaps you don't have enough tread on your winter tires.

Impossible : these tires were new in february 2000. So they are about ½ winter old.

What winter tires do you have? Also, if your inflation pressures are less than recommended you get less snow traction on the winter tires.

I'll check for the pressure. Maybe they're not inflated enough. I have Yokohama Guardex F340 (http://www.yokohamatire.com/04b3f.html). By reading that site, you are lead to believe that this is the ultimate winter tire... ha-ha... very funny...

By the way, do you need any lift to fit 265/75 tires?


------------------
Hugo Lafrenière
'99 SR5 V6 5sp

[This message has been edited by Hugo (edited 17 December 2000).]

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Jeff the marmot
Trailriding Forum Moderator


Reged: 02/13/00
Posts: 4679
Loc: Thornton, Colorado
Re: Is there any way to disable ABS?
      #261700 - 12/17/00 11:17 AM

quote:
Originally posted by RobJapan1:
Even if you have a switch ,you still have to turn the car off and start it up again for the ABS to turn on or off.

Not if you have the electric locker. I don't have to turn the engine off and on again every time I engage the locker. Exactly during the time that the locker is engaged, ABS is disabled. Period. That's why that's such a nice solution.

Also, the problem that I see with just adding a switch to "something" inside the ABS circuitry so that it senses a problem and disables itself is that the ABS system might log an error code to it's memory that cannot be reset by simply restarting the engine. I don't want to have to go to the dealer to get the ABS system reset/re-enabled. Like what Robert said, don't mess with this unless you're confident you know exactly what you're affecting. I don't yet, so I'm still working on it.

If you don't have the electric locker feature, then it would seem to me that you'd have to add a switch and a high current relay to the 60A ABS actuator fuse. You can probably turn ABS off while the engine is on, but you may need to restart it for ABS to be re-enabled.

One other thing -- I prefer having ABS enabled the vast majority of the time. It's rare when it doesn't act right and I want to disable it, but I won't know when that happens until I encounter it driving. That's why I'm after a switch inside (like where the hazard light button is) so I can hit it when I'm in a panic only if necessary.

Jeff

--------------------
Jeff
2000 4Runner SR5, supercharger, rear e-locker, ARB front locker, 285/75R16 MT/R's, custom bumpers & skids
2007 Tacoma double cab 4x4 - stock


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Anonymous
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Re: Is there any way to disable ABS?
      #261701 - 12/18/00 02:38 AM

Jeff, you're definately on the right track. From what I remeber from the wiring diagram, EX12 on the ABS ECU is what needs to be triggered to disable the ABS. And Robert, Jeff is also right about the electric locker equipped 4Runners being able to deactivate ABS and then reactivate it without restarting the vehicle. My 4Runner did not come with the locker (but it will be retrofitted this week!), I tried to wire up my ABS ECU so that I could disable the ABS when the locker is activated, but I've been unsuccessful thus far. My ABS ECU doesn't have a wire running into EX12, so I ran a new wire into the pin--but when powered, it does not deactivate the ABS. I'm guessing that there are slightly different ABS ECU part numbers for locker equipped and non-locker 4Runners (I'll check this out for sure on the parts microfiche in the next few days). So, Hugo, apparently this quick and easy option may not work for us (unless you want to replace your ABS ECU from a 4Runner that had the locker).
There may be another option though, I recall another pin on the ABS ECU that signalled a fault in the ABS system and activated the dash warning light. Maybe wiring up this pin will serve as an effective ABS defeat switch--however, I am concerned about the possibility of a computer somewhere storing all the fault codes as Jeff mentioned. I'll look into this as well, hopefully I don't end up frying the ECU with all this tinkering.
Before going through with the electric locker retrofit, I did tons of research on every aspect (and alternatives such as ARB) that I could. I bought the 4Runner in May of 1999, and I've been planning the retrofit since before the purchase!! (Since Toyota said "NO LOCKER FOR WEST COAST WEENIES with 5-speeds"). Well, during all the research, I found several Tacoma owners who were vary knowledgable about the ABS functions, and they told me about the different braking patterns. A quick look at the 4Runner factory wiring diagram confirms this as well as the deceleration sensor specifics--seems like 2wd 4Runners are screwed since it looks like they're not equipped with the deceleration sensors. This may also explain some of the complaints about 4Runner ABS that I came across on Edmunds some time back. I personally haven't seen the difference between the braking patterns, but I will definately test it out in the next few weeks while in snow country.


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Anonymous
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Re: Is there any way to disable ABS?
      #261702 - 01/06/02 10:32 PM

I want to have a switch to disable ABS, did anyone do it yet with an e-locker?

I also want to do the grey wire mod that allows you to engage the locker in 2HI & 4HI. I read about it on the tacomaterritory message board, didn't sschaefer3 do the write up on it? I looked at my 4Runner & I don't have a grey wire coming out of my 4wd computer. Maybe Steve Schaefer could post something on this. Thanks.

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Anonymous
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Re: Is there any way to disable ABS?
      #261703 - 01/06/02 11:02 PM

I found a write up on the "Blue Plug" mod that, I guess does the same or a simmilar thing. On the last AZ, TTORA run we all sat around and agreed that it would be best not to mess with it. That it would be a very expensive part to replace. So, for now, I'm not messing with mine.

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Jeff the marmot
Trailriding Forum Moderator


Reged: 02/13/00
Posts: 4679
Loc: Thornton, Colorado
Re: Is there any way to disable ABS?
      #261704 - 01/07/02 02:06 AM

I didn't get around to it yet. I have never heard of anyone that has done this mod.

It's not the same as the blue plug mod.
Jeff

--------------------
Jeff
2000 4Runner SR5, supercharger, rear e-locker, ARB front locker, 285/75R16 MT/R's, custom bumpers & skids
2007 Tacoma double cab 4x4 - stock


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Vegas4Runner
Wheeler


Reged: 08/10/00
Posts: 129
Loc: Las Vega$
Re: Is there any way to disable ABS?
      #261705 - 01/07/02 11:32 AM

Here's a write up for the grey wire locker mod.

I haven't done it yet, but I plan to try it out this weekend. I also don't remember the original thread on TTORA's board, but I'm pretty sure it was under the Cheap Trick section of their message board.

-Robert

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Jeff the marmot
Trailriding Forum Moderator


Reged: 02/13/00
Posts: 4679
Loc: Thornton, Colorado
Re: Is there any way to disable ABS?
      #261706 - 01/07/02 01:01 PM

That's also a nice link, but that's the locker mod for certain vehicles to be able to engage the locker at any time. Sorry, that's not what this thread is after.

The goal with this thread is to disable ABS by fooling the ABS ECU into thinking that the locker is engaged without actually engaging the locker.
Jeff

--------------------
Jeff
2000 4Runner SR5, supercharger, rear e-locker, ARB front locker, 285/75R16 MT/R's, custom bumpers & skids
2007 Tacoma double cab 4x4 - stock


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Anonymous
Unregistered




Re: Is there any way to disable ABS?
      #261707 - 01/07/02 03:10 PM

That's my boy Corey Schafer! But Jeff's right. That's not what this thread is about. 50 lashes with a wet noodle.

For what it's worth, thanks for the link.

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