ABS, Dirt Roads, and 4 Runners

[jmans]

I am the owner of a 2004 Toyota 4Runner SR5 with 4WD and a V6. As you know the combination of ABS and dirt roads can be dangerous. In addition to this, it is also a proven fact that ABS system will typically not function properly with 4 Wheel Drive and a locked differential (this may not be the case for a center locked differential). I would like to ask the following questions about my vehicle based on these two facts:

1) When is ABS NOT Active? That is to say, is ABS turned off when the 4Runner is in 4WD LOW and the center differential is locked? Or 4WD High with the center differential locked?

2) When VSC is turned off is ABS also turned off?

3) If ABS is not turned off, how do I stop in a reasonable amount of distance on Dirt and Sand (other then crawling along at an unreasonably slow speed, which does not always guarantee safety)?

4) If ABS is turned off, will the car automatically still pump the breaks?

5) Does break assist (activated by quickly pressing down on the break pedal) still use ABS?

I ask these questions to better understand how to safely operate my vehicle under different road surfaces and conditions.

 

[Thai]

Some answers:

1. ABS is always ON. I believe that it does get less sensitive when you're in 4-LO...but Toyota won't confirm that. However, i know that the Land Cruiser's ABS system is terrain adaptive...so, 4runner has probably the same software. (Of course, ABS comes on ONLY when there is slippage.) Also, i can't think of one midsize SUV that does not come with ABS standard...i know that there are a few miniSUVs that does not have ABS in their base model (CRV for example).

2. Nope. Remember that your 4-wd system is ATRAC (4-wheel active traction control system). It uses ABS sensors and brakes to provide 4-wheel traction. It is ABS for off-roading if you like.

3. Just slam on your brakes and be a good driver (aka anticipate dangers). First off, if you're going to go down a hill, then you should be in LOW range (aka crawling) and use DAC. Off-roading is about driving with control...it is not about racing across a terrain. I guess that you can try and find the ABS fuse and pull it...but i do NOT recommend doing this because this may screw up your 4wd system (see #2).

4. Since ABS cannot be turned off, this question is not valid.

5. Brake Assist is to slam the brakes for you when it senses that you want to. It has little to do with ABS directly. It just slams the brake pedal for you.

Hope this helps.

 

[Good Times]

Thai summed it up pretty well

Just food for thought though...

If you are planning to offroad in soft terrain, drive in 4hi and always lock your center diff (thus disabling the VSC). Always drive slow where you are always in control of your vehicle. If you feel the need to get into 4lo, get into 4lo before you are stuck (thus you can be in 4lo if you wish).

DAC works but only use it when needed as it really takes away the fun of playing

Enjoy and good luck!

 

[Greenhorne]

Re: Re: ABS, Dirt Roads, and 4 Runners

Thai summed it up pretty well

DAC works but only use it when needed as it really takes away the fun of playing

BUT, for some real fun... get on a REALLY long, step hill; engauge the DAC; let is start doing the work for you and the just touch the brakes. It will suddenly disengauge and you are flying.

I have found that the computer is able to control the vehical better than I in loose shale on a step decline. The computer will brake individual tires less or more as needed faster when it is the boss.

It sure is fun to play with.

ps. I have yet to run into any situation where the abs was a factor while off road. Yet of course.

 

[jmans]

Thanks Thai

Thank you for the information Thai. It helps, but I will explain the questions a little further.

I am not necessarily talking about off road but standard dirt roads which are actually considered on road in some places (maybe dirt roads can be considered off road). So these roads are similar to regular roads, they are just not paved.

Also, I understand that some people actually remove their ABS relays (or fuse) to disable the system when "off roading". I wonder if this is advisable with the 4 Runner?

I would also like to ask about this terrain adaptive ABS. Is there anyway to verify that I have it?

 

[Thai]

Well, i would be against removing the ABS fuse. With the 4runner, ABS system is integral with stability control, traction control, and engine management computer (dethrottling function when slippage is detected). So, if you remove this, then you will have a lot of dash lights going off. I am not even sure if you will be able to drive your 4runner because it is linked to so many other systems.

I have not gotten any solid answers from Toyota regarding terrain adaptive ABS. But, like i said above, i do know for a fact that Land Cruiser/LX470 does come with it. I see no reason for the 4runner not having the same software.

You can ask your local serviceman...maybe they have some Toyota handbook that can give more definitive answers.

 

[jmans]

ABS, VSC, and TRAC

Well I managed to get more of the information I needed. I found a way to disable the VSC, TRAC, and/or ABS anytime I want to. I can do it without compromising any of the other systems (except when ABS is off VSC and TRAC will not work as well).

 

[dancojgl]

Re: ABS, VSC, and TRAC

I found a way to disable the VSC, TRAC, and/or ABS anytime I want to.

Pray, tell...