ABS sensor revisions/compatibility
 

I had to replace the wheel hub assembly on my 2000 986 S and replaced it with a 2002, which has a different ABS sensor connector. I tried to remove the correct sensor from the old hub but it was rusted in there and snapped out.

I've cut the connector off the older, correct sensor, and I plan to just try to splice this connector onto the newer revision as I'm worried about snapping if I try to replace the entire unit.

Has anyone tried this before? It's a simple two-wire system that I assume uses Hall-effect magnetics and so simply closes/opens the circuit when the marking passes the sensor, but I'm just curious if anyone has knowledge which proves this won't work.

Get the right one for the car............

Thanks for that very unhelpful reply.

Not all of these systems are the same, different years used different number of teeth on the tone rings in the hubs which will send erroneous information to the system control network and result in codes that can NEVER be cleared. This is why the sensor connectors are different, to prevent installing the wrong style on the car.

Get the right one for the car......................

Ok, that's extremely helpful so I don't know why that reply wasn't the first one. Thank you.

Edit: but if the tone ring has a different number of teeth I'd need to change both that and the sensor itself to not risk those permanent codes... Right?

And you would need the appropriate ABS control module, as well as the matching DME software to accept its presence, and these would need to be coded to the car, but then the other three sensor/hubs would fault because they have become mismatched.

It is VASTLY easier and cheaper to simply use the correct parts in the first place.

And, my first response is still the correct one............

Simply "Yes" would also have been just as correct... And just as helpful. 🤣😉

When someone takes a questionable approach, I like them to know why it is questionable, it becomes a learning opportunity.

Agreed. But your first reply, although correct, was neither. That's why I made light of it. Nothing personal, just a joke.

Your second response, however, was extremely helpful and instructful.

And I think strtnz's follow-up question was about taking the tone ring off the original hub and putting it on the replacement hub. If that's possible to do, there'd be no need to get a new ABS module & DME, correct?

Apparently they already have a replacement hub and are hoping there's a way to make it work instead of spending more money to buy a separate one.

Yeah. I still have the original hub but it would need a bit more work to get it ready than the one I fitted needed. I didn't even realise the sensor connectors were different until it was all in place as that was the very last thing I connected. But I have the option of removing and replacing the ring or the entire hub, and both would require different work but probably a similar amount of effort in the end.

I'd love to know how it could create permanent codes though. If there is a realistic chance of this it would be silly to continue, but AFAIK the sensor reads 10101010101... in the highs and lows and reacts when either a 0 or a 1 remains for too long. Given the speed of the ring is dictated by the speed of the car, it can't be too picky about how many teeth and therefore signal changes there are in any specific second, minute, whatever. But as JFP said, the connectors are different for a reason...

Edit: ended up confusing myself a bit. ABS ring is on the driveshaft so the only thing I need to replace is the sensor itself, as the ring remains the original. So hopefully the sensor isn't stuck in the hub and it's an easy replacement 🤞🏼

My two cents worth is that JFP is always on the level and gives good advice. Sometimes "get the correct part for the car" sums up everything - terse as it may seem. I am watching the snow beginning to fall - again - here in Vermont. The Boxster is parked outside. I am using the garage bay for waxing the kayak and getting it ready for the water if spring ever comes.

The sensors themselves are different, not just the plugs. Use the pelican parts website to compare the two years and you'll see the difference. Having said that, that doesn't necessarily mean they'll send a different signal, given as you said, the ring is on the shaft, not the hub. And, BTW, my search found that the hubs are the same for both years so you're good there.

So, you have two options: 1) buy a new 2000 sensor, I'm not sure where your source is in the UK, but they're 107 USD at Pelican, or 2) cut and splice and hope for the best. It is my understanding that the "permanent" codes, while you cannot erase them, will go away once the problem is fixes. So don't go under the impression that it'll stick with your car forever.

Well, three, I guess... and that's to try and remove the original sensor. But you said it was stuck pretty good.

What would I do? Depends on what I'd want to do with the car. If I wanted to tinker and experiment with it, I'd cut and splice. If I want to finish it and do it right, I would definitely buy the appropriate sensor.

No doubt, he absolutely does. He's a wealth of information, and I appreciate it greatly. But when someone asks a question, "because I said so" doesn't help. Of course "get the right one for the car" is sound advice. But nobody comes here looking for Captain Obvious. They come here looking for information.

"get the right one" what? Hub? My research found that the hubs are interchangeable for those years, so the answer was not very helpful, was it? Something like "the sensors aren't the same and you'll set off permanent codes" would have been terse AND helpful. Peace.

Appreciate your input and knowledge. I like to learn and will give the splicing a go if there isn't an absolutely permanent risk, because I already have those parts and will be waiting beyond the annual inspection date for the parts go arrive anyway, so I don't really have much to lose.

I'm studying electronics engineering so I'll take this as a hands-on learning experience!

From JFP I would have been satisfied with a, "It's not a ****************ing Toyota".

New guy will learn to appreciate JFPs efficiency, or how to better employ Google.

:cheers:

You're welcome. Just keep in mind that it'll probably take at least 4 drive cycles after the problem has been corrected for the "permanent" code to clear, so don't expect it to go away overnight. I've never had those types of codes on my Porsche, but I've had them in my other cars. I freaked out when I first saw "permanent" on the scan tool. LOL. Then my mechanic told me to just make sure the problem is fixed and it'll go away. And it did. And let us know how it worked out, please.

Looks like the sensors may send a different signal entirely. It could be your 2000 has a passive sensor and the 2002 has an active sensor. One sends A/C current in a sine wave while the latter sends a digital square wave. If that's the case, you'll get an error code regardless of the tooth count on the ring. So, you're stuck with having to get the correct sensor.

Here's a helpful video:
https://www.youtube.com/watch?v=LC3jCyHjWqo&t=155s

Very helpful, thanks for sharing!

Perfect. Then I can test each sensor's output voltage and if they're in the same range I'll have a go at splicing, if they're in different ranges I'll know I need to buy an original sensor.