Why did this happen?

[PARAGON]

Originally Posted by Poopy

I think what he is saying, is that there is a sensor, it senses a pulse when the magnet or whatever it is goes past the sensor. It has no idea if its going forwards of backwards, its just passing a sensor. Lets go to a simpler example for you. Picture the speedometer you have on your road cycle, when you got the kid at the bike shop to install it he put a little magnet on your wheel and a sensor on your forks somewhere.

no, I think he is trying to think, which he shouldn't do. He might end up with an aneurysm

[Poopy]

Wow you are dense. Just cant admit to being wrong huh?

[PARAGON]

Originally Posted by Poopy

Wow you are dense. Just cant admit to being wrong huh?

Yes

[Boar-Ral]

Where are the actual sensors located? Are they located inside the axle casing, or at the actual wheel assembly? I have had my ABS light come on twice when offroading, and of course, because traction control relies on these sensors, everything shuts down. So I guess the root of the problem is something flaking out with the sensors, whether it be for the reasons others have stated, like excessive wheel spin, or something else. I was just wondering where the sensors were, because I was wondering if it was possible to get gunk in between them that might cause a problem. I am experiencing problems with the ABS sensors on my car at the moment, due to a wire harness that is almost torn out. Until the replacement gets here, it tends to flake out a lot right around freezing, when I think snow and ice melt and moisture gets in there. When it is really warm, or really cold, it is never a problem.

[Boar-Ral]

I only have a basic knowledge of how the wheel sensors work, but enough that I suspected that they should be able to detect wheel direction as well. I spent a few minutes searching and found that there are a couple companies that make directional wheel sensors for automobile manufacturers. They are essentially a normal wheel sensor, but the magnets on the inside of the sensor are staggered with their north and south poles reversed. Then, the outside of the sensor has two magnets, and simple electronics calculate the wheel direction based on what pole is encountered first and by what magnet as it circles the hub.

I called AM General to inquire what model of wheel sensor they use in the H2 and if it is capable of detecting wheel direction. They are supposed to call me back today or tomorrow.

[sj-x 500]

the sensors are typically located at the hub, on the back side of the hub there will be a type of gold or silver colored ring pressed over the outside of the hub. the pickup is held in the housing on teh rear axle, or in the caliper bracket usually.

the hub rotates, and the "sensor" which is just a magnet, with some thin coper windings around it, picks up on the raising and collapsing magnetic feild, which induces the voltage in the wire, sending a pulse to the ecm along the wires.

do you have a link to how a directional sensor would work?

[Boar-Ral]

Originally Posted by sj-x 500

the sensors are typically located at the hub, on the back side of the hub there will be a type of gold or silver colored ring pressed over the outside of the hub. the pickup is held in the housing on teh rear axle, or in the caliper bracket usually.

the hub rotates, and the "sensor" which is just a magnet, with some thin coper windings around it, picks up on the raising and collapsing magnetic feild, which induces the voltage in the wire, sending a pulse to the ecm along the wires.

do you have a link to how a directional sensor would work?

I had bookmarked a web site when the discussion first started, but I cleared them out yesterday, when doing housecleaning.

I did find another web site though, but this one seems to utilize the Hall Effect, and is different from the one I first found. You can read it here, though.

I also found this web site, where it indicates that the upcoming (or at least upcoming when announced recently) 4Runner will also be able to detect wheel direction, though they are pretty vague on details, apart from the basics that we already know.

While thinking about it further, I can see how you might be able to more easily detect wheel direction with a magnetic system. What if around the ring, you had magnets of increasing strength, and the system could detect if the field was increasing gradually, then sharp dropoff, etc. or decreasing gradually, then sharp rise, etc.? I guess the problem there would be that because the field is translated to voltage in a normal system, increasing voltage means increasing speed. This system I'm proposing would see increasing voltage, just in normal wheel spin, even if the vehicle is not accelerating. Hmm. Maybe there is a way to compensate for that. Maybe two equally-strong magnets on opposite sides of the ring, and the system uses those as "checks." (It would need two sensors on opposite sides of the ring, too, to monitor.) Sorry if I am rambling, and if I am a bit vague. Sometimes I wish I had the intelligence to be an inventor.

[Boar-Ral]

I forgot to mention that when I first contacted AM General, they indicated to me that they were unable to tell me the model of the wheel sensor because it was proprietary information. Proprietary does not seem to be the right word, here. Regardless, they would not provide the model number to me. When I contacted them again, and simply asked whether or not the sensor was capable of detecting wheel direction, they did not get back to me. Either they do not know, they are waiting on an engineer, or I pissed them off.