ABS warning light

[mik_ok]

Christ - is that what that noise is? [&:]

I've always thought there was something wrong with mine. (no for once I'm not being sarky).

 

[Fen]

ORIGINAL: slim_boy_fat

ORIGINAL: Fen

A kind of groan/whirr as you pass 6mph for the first time when you start up.

Pretty much described yourself there Fen []

No, that's 100% groan.

 

[carlmthompson]

I'm glad someone's now cleared what that noise was - it sounds like an electric wing mirror, which was confusing me!

I was pretending it was the Fuel Filler closing after leaving the pits[]

 

[944turboS]

Well latest is the car is booked into a Bosch agent on Friday.

 

[944turboS]

I had a similar problem with my Turbo. Look HERE for the answers I got. There are two more relays on the side of the pump as well as the one in the fuse box. I took mine to a Bosch agent for diagnosis in the end only cost an hours labour & I had the answer, was a rear sensor on mine.

 

[sawood12]

Was it an intermittent fault? Something a bit strange happened to my ABS for the first time tonight whilst sat in traffic I heard a funny rapid clicking noise for a few seconds that seemed to come from behind my dashboard and the big red warning light illuminated along with the ABS light. I continued my journey and stopped of at some shops on the way but when I started the car up again everything was OK.

 

[944turboS]

My warning light was on permanently after the car came out of hibernation last month.

 

[chrisdenton]

Mines on permanently too, thanks for the advice Graeme, I'll have a poke around over the weekend (if you'll forgive the expression). Was there a final conclusion to the MOT question?

 

[944turboS]

The conclusion ref the MOT seems to be

No ABS = No MOT

It looks as if I was lucky in that respect as mine got passed with the fault.

 

[ScottishSpyder]

The abs light came on on my 944 Turbo. Specialist ( Brian Miller )couldn't find anything but said it my be when the battery has less than 12V as this seems to bring the light up, e.g. after hibernation although I do have it on a trickle charge.

 

[Guest]

ORIGINAL: 944turboS

The conclusion ref the MOT seems to be

No ABS = No MOT

It looks as if I was lucky in that respect as mine got passed with the fault.

Mmmm thats not the case but i will let it go, with the comment, they DO NOT test the ABS for the MOT. Everyone can go on about lights etc etc yada yada yada, what they test is a light (and even then probably only 50% of tester will )

But there you go.

Oh and BTW my car passed 2 MOTs with NO ABS.

Thankyou..

p.s. i am not advocating running without ABS just telling it how it is.

No doubt someone will be along to tell it how it isnt, but thatts what makes forums so much fun. []

 

[Christopher I Ralph]

Here is the appropriate extract from the MOT Tester's Manual:

Method of Inspection

This ABS inspection applies to all systems fitted as 'standard', and to 'optional' systems fitted.
When testing vehicles that have ABS fitted the road wheels should not be allowed to rotate clear of the standing surface with the ignition on as this can cause the ABS system to indicate a fault which may require specialist equipment to rectify

Missing components
Where a vehicle is presented for test with an ABS component obviously missing but, follows the correct sequence of operation, the defect must be brought to the attention of the presenter.

If the vehicle is fitted with an anti-lock braking system, check that

a. a warning lamp is fitted
b. the lamp illuminates
c. the lamp follows the correct sequence of operation
d. does not indicate a fault.

Note: The sequence varies with the type of system. Refer to the manufacturers or other reliable data, eg purpose produced charts, books, etc. 1. The warning lamp

Reason for rejection

a. is missing
b. does not illuminate
c. does not follow the correct sequence
of operation
d. indicates an ABS fault

My problem is that my ABS light does not go out! This follows a short period (about one month) of non-usage.

The following link is very useful for running tests on the sensors:

http://www.topbuzz.co.uk/maintenance/testing_abs/testing_abs.htm
HTH

Christopher

 

[chrisg]

At the risk of contradicting Fatboy slim.....

I recently overhauled and fixed the ABS on my Turbo.

Costs - £70 + VAT for mint condition second hand ECU - Porschapart

£75 + VAT for a filthy but perfectly working pump - PH Sportscars.

Total bill = £170 inc some sealant to put the front wing back on with.....

That's assuming you do all the work yourself !

 

[Diver944]

First thing is to ditch that mechanic [8|] All S2's have ABS as standard (unless it's been removed for some odd reason [&:]). First thing would be to 'safely' test if your ABS is working, find a clear damp road or empty car park and slam the brakes on from a low speed like 20 mph and you should feel the pedal pulsing as the brakes lock and release.

The system is fairly straight forward and it is probably one of only a few components to cause the error: the ABS sensors, the wiring, the ABS ECU or the ABS pump

1. Each wheel has a diamond shaped sensor behind the brake disk that senses teeth on the hub as they rotate. These sensors can get very dirty which will sometimes trigger the warning lamp.

2. The sensors connect to a wire that lead back to the ABS ECU in the drivers footwell.

3. The ECU controls the pump when to release and apply the brake pressure.

A good Bosch mechanic can plug in to the system to perform some basic diagnostics, I think you need to find one other than your local mechanic. Whereabouts in the country are you and maybe someone can recommend a nearby specialist.

 

[Big Les]

I had a similar problem, and after a lot of investigating the brake system I took it to a local car electrics specialist. He was able to put a meter on different pasrts of the wiring and he discovered that the wiring for the warning light had corroded (or the sleeving chaffed through) and the wire was touching the bodywork and causing a short which made the light come on. If I remember correctly it was where the wiring comes from the rear brakes along one side of the body to the engine compartment. So it may have been the pad wear sensors wire and not the ABS?

 

[chrisg]

Andy

Paul is absolutely spot on with his description/ diagnosis. In essence the ABS on the 944 is very basic and very 'modular' with four sensors, a pump, a brain and assorted wire/ sensors in between.

Without looking at the car its very difficult to diagnose the exact problem, but if you can get it to a local 'expert' or Bosch technician they should be able to diagnose it pretty quickly.

First thing to do is to clarify whether the ABS is working or not, just because the light is on or off doesn't mean its functioning/ not.

Give me a ring if you need any help, as I changed/ fixed all the ABS on the Turbo S last year.

07793 369 509,

Chris

 

[944 man]

If it passes the self-test when you turn the ignition on, then Id suspect the wiring. If it does turn out to be the ABS controller, then it should only cost a few pounds from an extablished breaker (because they seldom ever sell. If you buy from one of those list every screw at a stupid price skankers who 'trade' on t'internet, then who knows what theyll try and charge?).

Simon

 

[evoboy69]

I don't have a warning light saying I have a fault but I don't think the ABS actually works.

Maybe oldschool ABS allows for ALOT more lock up?

 

[Neil Haughey]

ORIGINAL: 944 man

If it passes the self-test when you turn the ignition on, then Id suspect the wiring.  If it does turn out to be the ABS controller, then it should only cost a few pounds from an extablished breaker (because they seldom ever sell.  If you buy from one of those list every screw at a stupid price skankers who 'trade' on t'internet, then who knows what theyll try and charge?).

Simon

[] I am pretty sure who you are talking about here, ISTR he charged me 150 quid for mine. I am definitely in the wrong business.

 

[Neil Haughey]

ORIGINAL: evoboy69

I don't have a warning light saying I have a fault but I don't think the ABS actually works. 

Maybe oldschool ABS allows for ALOT more lock up?

No you will hear it more then feel it. If you brake hard and hear a hooting sound from the footwell/scuttle/front wing area then that is the ABS working. TBH it is pretty old fashioned and allows much much less lock then modern systems. I found this when testing back to back against my old Saab 9-5 using the G-tech pro. The Porsche system maintains excellent vehicle stability whereas the more modern system in the Saab allows a wheel or 2 to lock a few times. The benefit is shorter stopping distances but the car is really unstable braking like that and darts about on the road. I know which I prefer.