Problem with ABS on Polo 2001 1.4L

[lyonelk]

Hi everyone,
as I saw tonight on your great website, I encountered 2 months ago the "famous" problem of the ABS light which comes on sporadically. Generally and as far as i remember, the ABS light does not come on when I start the car in the morning. Also, when i stop the car for a few hours and I start it afterwards, the light is never on.
It seems that the ABS light comes on only after a few km.

I've been to the official VW garage where i always service the car, they've plugged the diagnosis machine and it says "ABS pump fault - sporadic level" (I don't remember the fault code - If needed, i can go and get it). Their diagnosis is that the ABS pump seems to start being faulty and that it needs to be changed.
After they plugged the diagnosis machine, they perform a reset of the " computer" (sorry for the technical terms... english is not my mother tongue) and the fault disappears. And of course, after a few km (or mins, hour, days) the light comes back.

However, sometimes, when the ABs light is on and that I switch off and then on the engine, the light comes off. And of course, after a few km (or mins, hour, days) the light comes back.
Then, sometimes also, when driving with the ABS light on and that i switch off and then on the engine, I can hear 3 short piercing sounds and after that the light comes off. And of course, after a few km (or mins, hour, days) the light comes back.

Do you have any idea of what are these 3 short piercing sounds?
Do you have any idea of where the problem can come from? and is there a way that one of the sensors is faulty instead of the pump itself?
If any question... please ask

Thanks a lot for ur precious help.

[lyonelk]

Nobody knows? :-(

[lyonelk]

What a surprise...

I had to replace my battery because it was really low...

and surprise... the ABS light does not come on... everything seems to be ok...

does anyone has an idea about what is that?

[stuart]

Strange!!!

I know that by disconnecting the battery it can reset the main ECU (Computer), so maybe it was just an error that has now been reset.

No other explanation

Stuart

[lyonelk]

Well,
2 months ago... my alternator died... (my battery was still "alive" --- wounded but still alive")

the light didn't come back on for approximately 1 month & a half.

I was not really surprised that changing the battery would help.

the question is "for how long will it help?" difficult to know...
the place where i service the car (a VW garage) has no explanation...

I wonder if the car equipments do not start malfunctioning as soon as the power starts to become a bit low.
I know that the garage has reset twice the ECU... however it did not solve the pb!

Does anybody know where i can find some data on the braking system for my polo? I mean some schematic... diagrams... maintenance instructions... I want to understand how this system really works...

Thanks