ABS Failure!
 

During an autocross yesterday, my ABS went out and the OBD says ABS FAILURE and the ABS idiot light is on. I have only basic ABS, no PSM

Brakes work fine, just no ABS.

I have a new found appreciation for ABS. Without it working, its really easy to lock up the brakes.

In searching, it could be a wheel sensor that went bad. I did find some info on testing them with a OHM meter, but there were several values mentioned and I don't know what the correct one is.

Anyone have any thoughts on troubleshooting the problem?

What codes?

Maybe as simple as a speed sensor wire coming loose, they plug in next to the brake wires on the wheel carrier. You probably had them disconnected when you put your new suspension on, maybe one got loose? (although they are retained by that metal.clip)

I can't recall if you have a durametric, that might tell you which wheel? Sending pm.

Got your PM Steve. Thanks for the generous offer. I Have a durametric

What a great forum!!!

Once it finally connected to the ABS system, I found a 4210 code- Rt rear sensor
I also have a P0501 code which from what I have read, is a fault in the same sensor

JFP, is that correct?

Is there a way I can bypass the sensor and see if that clears the fault?

Ill pull the wheels tomorrow and check the connections.

I'm away from the shop at the moment, so working from memeory P0501 is for no speed signal, which can come from multiple sources:

Break or short in the wiring from the ABS module to the ECM

Break in the wiring from the left rear wheel speed sensor to the ABS module

Left rear wheel speed sensor is dead.


Pull the left rear wheel and check for a damaged sensor or heavy build up of brake dust. If OK, check the speed sensor for resistance, should be 1.6-1.6K ohms.

Thanks

I would not normally question you, but the 4210 code explanation I got says right side, not left. Since you said you were away fro your shop, that makes a bit of sense

I checked the left and right sensors and the left one reads 1.7k and the right .4k

I swapped out the right sensor with one from my 996 and ABS works properly. I cleared the codes and will see if the P0501 comes back

Thanks

Good for you..!
A lot of people (ok, ok, my wife..) always question the reason of a garage full of spare parts.. LOL

As I mentioned, I am away from he shop at the moment, so I do not have access to my OBS II manuals and am going purely from memory, but I do recall P0501 as being a communications issue for the left sensor on a Boxster. Off hand, I do not recall the 4210, so I did not want to guess on that one. I just placed a call to someone that does have access to the manuals, and he confirmed P0501 as being the left sensor. He also drew a blank on the 4210 code.

If you got it fixed, more power to you, but P0501 is for the left sensor.

Thanks JFP

You go above and beyond on helping everyone. :cheers:
If I ever get out your way, I'll be bringing a bottle of your favorite libation

Enjoy the 4th with your family and friends!

OK, mystery solved: On the earlier cars, P0501 if for the left rear sensor, on the later cars with the newer DME (7.8), P0501 moves to the other side:

https://www.6speedonline.com/forums/...1&d=1329264650

So you are correct, and I should not try to work from memory...............

Don't you just love that fine German engineering?

Porsche has done stuff like this before, P1128 and 1130 mean extremely lean mixtures on DME 5.2, and extremely rich on DME 7.2 and later. I think they do it to sell more OBD II manuals at $1800 a pop.............. Does keep you on your toes however......

That's why you are worth the big bucks :)

Well, good news!
Replaced the right rear sensor, cleared the codes and all is good :cheers:

Have driven the car for a few days and no codes returned

Total cost to repair......... $30 for a used sensor on ebay

+ 1 on JFP :)

Is it the right or left for a year 2000?

Per JFP, depends on what DME version you have
See post #10

In any case if you don't know, they are easy peasy to change, so change one side if that doesn't fix it, swap to the other side

Ok thank you. I did not realize they were interchangeable. The exact answer I needed Jay. Thank you!