2004 Toyota Yaris ABS issue but no light

[jamescurryy]

Hi guys, just bought a 2004 Toyota Yaris 1.3 Spirit Auto, 58k Miles. It has an issue where the abs is kicking in when coming to a stop, maybe 1-2mph it kicks in and can hear it and feel it through the pedal. No lights come up on the dash and no codes are stored. I have taken the two front abs sensors out and cleaned and replaced then with no luck, the car has three new tyres and one nearly bald one on the back. This wouldn't cause the problem woukd it? Or can anyone else recommend what to do?

[flash22]

Does the light come on with the ignition eg. self test

Are the tyres all the same size, part worn "new" tyres or brand new tyres ? the abs will throw a fit if it detects a slip or different rotational speed

 

If its bald it's not road legal, its 3 points and £100 fine if caught, it's very dangerous to drive esp with all this rain lately

[Madasafish]

At that age, there may be corrosion on the ring on the driveshaft - or it is cracked. Or dirt on the sensor but you cleaned them..

 

A BALD tyre will certainly cause an ABS issue but it is the rear and not much braking effort there..

 

You really need to find out which wheel is affected as that will narrow down the search...Swop the bald tyre for the spare if it is better and try again.

[Sooty]

Get that bald tyre removed and replaced with a good one.

[jamescurryy]

Hi guys, thanks for the reply, have ordered a new tyre for it. The car isn't being used I bought it to sell on as was cheap with abs fault. Light comes on at ignition but doesn't come on when abs activates. There is an advisory in most recent mot for the light coming on though. 

[Gerg]

As above, if there is a faulty ABS sensor or a cracked or dirty sensor ring (an obvious 'castellated' ring on the driveshaft, as you probably know), then the ABS ECU will think it is genuinely detecting wheel slippage, and operate the ABS.  It will not 'know' that this is a false operation, so no error light will come on.

Whilst I've not needed to try this, and it is a little fiddly, if you can connect a voltmeter on the lowest AC volts range, across the pair of pins that go to the ABS wheel sensor connector, then you can measure the voltage when you rotate the wheel hub by hand.  The voltage generated will be small (it's speed dependent), but you could compare this to the other sensors.  If one is lower then that is likely the wheel with the problem, and it's probably that sensor.  But this will not detect a cracked sensor ring, as far as I understand it (?). 

There are probably plenty of YouTube videos to explain this technique more fully.