Yaris - Possible Abs/braking Issue

[Mike Heighington]

I have just been on the phone after leaving my wife's Yaris (03 plate) with our garage. Same problem with the ABS cutting in for no reason. All checked over but still happening. The garage has another Yaris just in with the same problem. He's asked me to drive it around and will look at it next week to see if he can fix it. The problem is trying to find which wheel is causing the problem. I will keep you posted.

[FROSTYBALLS]

Split into new topic from 11 year old topic

[Devon Aygo]

Can you trigger the fault through driving as if you can the issue can usually be spotted by driving, triggering the issue whilst the car is connected to a suitable diagnostic computer and watching the speed signals of all four wheel simultaneously, what you will normally see is is momentary/sudden speed difference on one or more wheels this is the trigger causing the ABS act.

The most common cause is corrosion of the hub between the tip of the ABS sensor and the face of the wheel bearing which includes the magnetic trigger for the ABS sensor, the corrosion causes a disruption the magnetic field which disrupts the ABS sensor altering its output, cleaning & treating the corrosion usually sorts this although don't expect 19 year old ABS sensors to come out without a fight.

[Mike Heighington]

Thanks Lee, I will pass this on to my garage to go a bit further on the diagnostics as you have mentioned. I will also try driving the car and braking round the local car park this weekend when it's clear of cars. Good tips and thanks again.

[m456an]

Have you changed any of the rear wheel bearings? If yes, it could be the new wheel bearing. 

 

If no I would simply try to clean both rear connectors they come out with a small screwdriver. Spray them with contact spray, then put some dielectric grease on them. 

[flash22]

the rear sensors are prone to water ingress - given its age the magnet in the bearing maybe starting to fail