ABS Light

[DrRobin]

For the last 3 mornings the ABS light has stayed on after start up. If I stop the engine and start up again, it goes out as normal and it doesn't stay on in the evening.

My battery was a little low so I put a little bit of a charge in it last night, but the ABS light was the same this morning. Could it be cool damp air, but I haven't had the problem before.

I checked for fault codes whilst the light was on, but didn't see any, although the fault reader I used might only read the basic codes, I have another reader that should read the codes.

If I can't find any codes what are the things to check?
- Sensors;
- Brake pads;
- Wear limits (do they light the ABS?);
- ABS pump;
- Something else.

Thanks

[JFP in PA]

Originally Posted by DrRobin

For the last 3 mornings the ABS light has stayed on after start up. If I stop the engine and start up again, it goes out as normal and it doesn't stay on in the evening.

My battery was a little low so I put a little bit of a charge in it last night, but the ABS light was the same this morning. Could it be cool damp air, but I haven't had the problem before.

I checked for fault codes whilst the light was on, but didn't see any, although the fault reader I used might only read the basic codes, I have another reader that should read the codes.

If I can't find any codes what are the things to check?
- Sensors;
- Brake pads;
- Wear limits (do they light the ABS?);
- ABS pump;
- Something else.

Thanks

You need to scan the vehicle with a Porsche specific diagnostic tool (PIWIS, Durametric) in order to see the codes. Without those codes, anything would simply be a guess.

[DrRobin]

My Autel code scanner found the error as

4210 - Speed-sensor wire, rear right

I am guessing that is either a bad connection or the sensor is failing? I have read that a good sensor reads about 1.8kOhm.

I don’t know if you can point me towards a guide for stripping the sensor out?

The ABS light didn’t stay on this morning.

Thanks

Robin

[Teddyonine]

I had a similar issue with my 03. I replaced the brake switch. It’s a simple procedure ( search here for a thread on how to do it) but you will have to be willing to contort yourself in order to access the switch in the footwell….haven’t had any problems since…..

[JFP in PA]

Originally Posted by DrRobin

My Autel code scanner found the error as

4210 - Speed-sensor wire, rear right

I am guessing that is either a bad connection or the sensor is failing? I have read that a good sensor reads about 1.8kOhm.

I don’t know if you can point me towards a guide for stripping the sensor out?

The ABS light didn’t stay on this morning.

Thanks

Robin

Hope it is a wiring issue as the speed sensor itself is imbedded in the hub bearing and requires replacing that bearing. Along with a resistance spec, the sensor in question should generate an AC millivolt signal when the wheel is spun.

[DrRobin]

Right rear ABS sensor reads about 1M Ohm, guess that means it has gone open circuit?

The sensor is on the outside of the hub secured in place by an Allen headed bolt, not sure if it is going to come out, I have seen videos where it is stuck in and needs to be drilled out.

The cable is stamped 00 907 909 966

Robin

[DrRobin]

Photo of the ABS sensor

[DrRobin]

Hi,

The sensor started to move, but snapped leaving it in the hole.



I assume I have to drill it out but what do I need to strip off first?

Robin

[DrRobin]

New sensor ordered.

Just a thought, the centre of the sensor is metal, with a plastic outer.

Do you think I could drill it and use a thread extractor to pull the broken sensor out of the wheel? If the metal part comes out, I am guessing the plastic part will be easier to get out if it doesn't come out together?

Otherwise, I don't have time or space now to strip the hub apart so it will have to go to the local garage for them to do.

Ta

Robin

[DrRobin]

Good news for me, the old sensor came out without removing the hub. It had to be dug out, but the last little bit was loose and came out with a pair of tweezers, so nothing dropped in to the hub.

I then put a piece of cotton wool soaked in bearing grease in to the hole to act as a plug and then cleaned up the hole. Finally removing the cotton wool and inserting the new sensor, a quick check and the fault cleared.

Hopefully I have got away without damaging the wheel bearing (I checked the bearing for play after a test drive and it was ok, no noise and no play) or CV, but I have break down cover and if there is any problems the local garage can get it to replace.

Thanks guys, another repair completed.

Robin