[jenkinstod]

I'm new to Toyota Nation, so let me know if there's a better way to ask my question below.

I have a 2004 Highlander with a little over 222,222 miles (yes, just went through all 2's!), and for the past couple of years, I've been experiencing a periodic problem that I believe is related to the anti lock break system (ABS). It happens when I'm driving at highway speed, or at least that's the only time I detect it. The car would start pulsing, with what felt like the breaks pulsing at a pretty high rate. If I pressed the brake pedal, the pulsing significantly increased, so I'm fairly certain it's related to the brakes. In all cases so far, this only lasted for a few minutes, then the car went back to normal.

When it first started a few years ago, the pulsing only happened once every 6 months or so. Recently, it has started happening more frequently, several times a week. It's typically been happening first thing in the morning, on my way to work. It still only lasts for 2-3 minutes.

One other potentially related factor is that I've had a tire pressure warning for several years. I've checked the pressure many times, and reset the warning several times, but it keeps coming back. I've heard that the pressure sensors on this model use wheel speeds, and if that's the case, I'm wondering if this is related to the ABS issue above.

One other factor to consider. I live in Houston, so I really don't think I will ever need ABS functionality. I know there's always a chance of ice on the roads, or maybe gravel or loose material, but all of the above are very unlikely to occur with this vehicle. As a result, it seems like disabling the ABS might be a good option, if possible.

Thanks in advance for any tips or advice, and please let me know if you need any other information.

Todd

 

[funman1]

You should HEAR ABS pump going if it's actively working.
To me it sounds like you have a sticky caliper and warped rotors.

 

[jenkinstod]

Thanks for the response. Just wondering, though, wouldn't those problems, especially warped rotors, exhibit themselves pretty often? Nothing has really happened for the last couple of days, which just makes me think there could be some sort of computer/circuit that's turning it on and off, even though it's not needed.

 

[funman1]

If you MASH the brakes in a parking lot and force the aBS to engage does the light come on the dash when it activates?
It does in my 2nd gen, and so by that method you should be able to see if the light comes on when you are driving normally too?

 

[jenkinstod]

Finally found a good parking lot where I could really slam the breaks. Did so 2-3 times, and although I could feel a little pulsing in the breaks, I never saw any ABS or other light on the dash. This clearly seems like an electronic issue. It doesn't happen often, but when it does, it frequently comes and goes quickly. So my question remains; can I disable ABS on this vehicle, and what is the impact of doing so? Thanks.

 

[funman1]

I guess you could disconnect the ABS pump power?
No clue what the ramifications of that would be?

 

[Bitter]

Probably a failing wheel speed sensor or wiring, but it would be hard to catch being so uncommon. Make sure the tone rings are clean and clear of debris and the sensor ends clear of stuff stuck to the magnet. A cracked tone ring would present all the time I would think, but take a close look for that too. On a Lexus I saw where the stainless steel collar had been pushed against the tone ring and ground the teeth down so the sensor got weak signal all the time which causes weird behavior.

 

[jenkinstod]

Thanks for the ideas. Not sure yet what tone rings are, but will do some research and take a look at them. Will post again if I discover anything or have additional questions.

 

[Bitter]

its the toothed ring on the axle that the sensor reads.

http://www.autoserviceprofessional....t-abs-wheel-speed-sensors-what-could-go-wrong

 

[Jesse Catlin]

Finally found a good parking lot where I could really slam the breaks. Did so 2-3 times, and although I could feel a little pulsing in the breaks, I never saw any ABS or other light on the dash. This clearly seems like an electronic issue. It doesn't happen often, but when it does, it frequently comes and goes quickly. So my question remains; can I disable ABS on this vehicle, and what is the impact of doing so? Thanks.

There is a fuse for the ABS system and you can pull it - ABS and brake lights will be on constantly though. I have 387k on my 2003 Highlander, recently acquired from my friend that put 210k on it (I wanted an AWD vehicle and figured why not, it still runs LOL), and he pulled the fuse becauuse the ABS would pulse under all normal breaking conditions - wasn't terrible for braking or anything but annoying and he didn't care about having it - he drove like this for about a year.

I will be tinkering with it, as I want ABS for when my wifey drives it (she's Colombian and this will be her first Boston winter driving...), and the feedback above for fixing looks pretty accurate in my experience with other ABS systems (wheel sensors, ring grinding teeth etc). If you don't really need it, though, I haven't seen anything adverse from the fuse being pulled.

 

[jenkinstod]

ABS Fuse

Thanks very much, Jesse. I guess the fact that the brake lights are on continuously means that I would lose some functionality. What aspects of the brake system would I no longer be alerted to, since the warning light is on non-stop?

Also, can someone please give me a web site that shows all of the fuse locations on a 2004 Highlander? I know the fusebox covers have maps, but the short descriptions are not always clear to me.

Thanks,
Todd

 

[funman1]

Brake lights on constantly is a major safety issue.
I would put the fuse back and attempt to disconnect the pump motor directly.. Brake lights on is a deal breaker...

 

[jenkinstod]

Dash Brake Light

I don't think they were talking about the brake lights themselves, but rather the brake light on the dash. Assuming that's the case, I'm just trying to confirm what the impact is of having that dash light on all the time.

 

[funman1]

I don't think they were talking about the brake lights themselves, but rather the brake light on the dash. Assuming that's the case, I'm just trying to confirm what the impact is of having that dash light on all the time.

Hoh gotcha, yeah if it's just the dash light a nice piece of black tape will do very well
But I mean keep in mind you now have one less safety feature too...

 

[Bedbug]

and ZERO cruise control (if equipped)

 

[jenkinstod]

So I'm trying to confirm what safety features I lose if I remove the ABS fuse. Can anybody tell me? And per the other post, do I lose my cruise control?

 

[Oveur Engineer]

I'm gonna go out on a limb here and say that one of the safety features you will lose is ABS.

 

[Bitter]

ABS, Traction/Stability control for sure, probably cruise control but that's not really safety.

 

[jenkinstod]

Thanks for the feedback. Just to clarify, the only reason I'm considering it acceptable to lose ABS is that I live in Houston, and haven't driven on any icy streets the whole time I've been here, 5-6 years. I feel like the risk of needing ABS is very low. I'll do some research separately on any other impacts of removing the ABS fuse. Thanks again.

 

[Bitter]

Well ABS comes into play in any situation where you might lock a wheel up, dry roads even under hard braking can activate ABS, wet roads for sure.