[Mk2] [Generic] ABS activating at low speed

[sam1176uk]

Recently changed the rear hub, drivers side, abs sensor as well and now the abs seems to be activating when i'm parking at 10mph or below, not all the time but about 50% of the time, any idea if this is a sensor issue or something else?
The abs light is off.

Cheers

[sam1176uk]

Can anyone help at all with this as nobody i know can shed any light on the matter and my local garage is stumped

[lemonyfresh]

mine does this as well :S
it would be interesting to find out why

[sam1176uk]

What does yours do exactly? Thought i was the only one, nobody else i've spoken to has heard of this before!

[lemonyfresh]

rarely when im pulling up to a junction at extremely low speed, or in traffic jams (again at about 2mph) it activates (i can feel the pedal pulsing away) until i release the brake. It doesnt hinder stopping distance but it is annoying :S

[raptor95GTS]

mine only does this if there is gravel or the perfect bump. In fact one junction I can get it to do it every time if I play dumb. Usually I just ease off the brakes then reapply fully after the bump or brake hard before the bump then coast through it to the stop line (which is like 10 feet beyond the bump). This is all slowing from 30mph so it's nothing like the speeds you are mentioning but it is at slow speed after inital braking it occurs

[Warner]

I had this with a megane worked it out too be that the ABS ring on the shaft was incorrect. The sensor is fairly simple, metal passing by a magnet to generate a voltage. the voltage will increase and decrease dependant on speed. If the sensor is slightly too far away at low speeds i will not generate enough voltage to send a signal to the ECU. ECU reconises the wheel as being locked therefore applies the ABS.

May be something totally diffrent. I ended up having to fit a new shaft as the wrong one had been fitted.

[sam1176uk]

That sounds right Warner, so can the sensor be moved closer to the ring, is it not a preset distance away from it though?

[Warner]

Generally the sensors are fixed in position, have you had a look to make sure its not covered in poop. Was the rear hub you fitted exactally the same as the one that came off? Tried the old sensor?

[sam1176uk]

Gave the sensor a good clean up when it was fitted, maybe give it another try tomorrow if i get time! Yes the hub was the same.

[Slarty]

It might be worth checking that you've fully engaged the ABS sensor into the hub while you're at it.

The large O ring can make it a tight squeeze into the hub so smear a fine layer of grease over it before you put it in and it'll go fully in much easier.

[sam1176uk]

Well took the sensor out tonight and gave it a good clean up, disconnected the battery to reset the ecu and... STILL doing it

How annoying...

[sam1176uk]

Does anyone know if I have a faulty sensor will the abs light come on or not?

[Lewis Jay]

If the sensor and/or wiring is "OPEN CIRCUIT" it should bring up w/light.

If its high resistance in the sensor/wiring then you may get the issues you describe without a w/light.

[sam1176uk]

I'm getting no light, how do I fix high resistance in the sensor then do you know?

[Lewis Jay]

You will need a new sensor, have you checked the resistance values already?

0.9-1.5 k/ohms sensor resistance

Have a read though the BGB ABS section.

http://www.mr2-tech.com/bgb/mechanical/ ... system.htm

[sam1176uk]

No haven't checked them as I would have no idea how to do so
Seems my garage may have damaged the sensor when removing it to fit the new hub then?
Think they are over £100 each am i right, are they all the same i.e osf/osr/nsf/nsr?

[Lewis Jay]

Yes its very likely they damaged it when changing your hub, they are very difficult to get out.

Second hand one will do mate, just put a post in the wanted section.

Pretty sure all four are differnet you will need the exact side.

[sam1176uk]

Cheers Lewis.

[sam1176uk]

Ok changed the sensor over today for the one i had in before i changed the hub (so i know it works) and the ABS light is now illuminated. Obviously i am now not getting the problem where the abs activates whilst i'm parking but that's because the abs is now not on at all!
Does anyone have any other ideas as my garage is completely stumped too and Toyota will take a fortune to look at it???
Please help lol