ABS constantly on!

[Paulgo]

Just developed a ABS problem - its staying on all the time! It doesnt seem to matter if I switch the ABS on or off (its a 3B). I can hear the ABS pumping away and feel it through the pedal

Started immediately after I started up this afternoon (fine on the drive before I parked the car up!) The ABS light came on and the car felt a bit juddery (I actually thought I'd left hand brake on!)

ABS light has stayed off since and the light comes on with the switch - but the ABS is staying on!

Any thoughts? Cheers!

[S2central.net]

Pull the fuse for it... or pull the relays from under the ABS cover in the engine bay.

Such a reset might tickle the controller out of some confused state - but they are pretty robust... Maybe down to frayed wires or dicky relay that is upsetting it. Sadly the 3B version doesnt push out fault codes either.

[Paulgo]

Cheers - I'm not sure which fuse coves the ABS (cant see anything on the fuse box ) but Ive pulled the two relays on top of the ABS pump. There's still a vibation though the pedal when I push down - tho I cant seem to hear the ABS clicking away as it did earlier. This is with the car idling tho and not being driven.

[s2_wot]

Possible:
ABS sensor pushed too far away from the sensor ring so the valve is getting a false reading.

ABS ring on one hub is full of dirt.

@Paul is the valve permanantly powered or powered from the brake light circuit like the early abs systems? Could there be a fault in the brake light switch?

[chezz]

Started immediately after I started up this afternoon (fine on the drive before I parked the car up!) The ABS light came on and the car felt a bit juddery (I actually thought I'd left hand brake on!)

ABS light has stayed off since and the light comes on with the switch - but the ABS is staying on!

Any thoughts? Cheers!

This has happened to me previously...The diff lock IS also engaging - It can be a problem when you are travelling at 60mph + on normal roads.
Not sure if there is a black box that resembles a 'spam tin' under the back seat...it has connector attached to it and this should disable the diff issue.
I seperated all the sensors and crudely compared resistance readings with a multimeter into the lead going to the hubs, I found one that was way off and replaced it.
If you cannot resolve the diff lock issue you will have to stop driving the vehicle!
It is extremely dangerous, knowing you have a problem of this nature and continuing to drive the vehicle, will render your insurance to be void.
I hope you manage to sort it out soon!

[spink]

1 way valve under rear seat is quite likely.

[Paulgo]

Thanks for all the replies guys - the good news is that things seem to be back to normal . I reset the fuse, so not sure what was up!

I dont think the diff lock engaged at all @Chezz - probaly just my imagination and a mild panic when I pulled away and I'm pleased to say it hasnt come on at all since!

Other than briefly coming on at that time, the ABS light stayed off and came on as normal with the hand brake warning light on ignition. I'm assuming that the light would've stayed on had there been a problem - and it was also odd that the ABS switch, other than making the check light come on, didnt make any difference either. So, couldve just been some muck on the sensor on what was quite a hot afternoon - but I'll take up to my local garage to have a quick inspection anyway!

thanks again guys - just releived it doesnt appear to be anything serious (touch wood!) Means I can get on changing the pads on the wife's Beetle

cheers

Paul

[Benjinkan]

Possible:
ABS ring on one hub is full of dirt.

Definite possibility, something similar happend to my old VR6 Corrado.