I just changed both front wheel bearings on my Skoda Octavia Mk3 RS. After changing the bearing I went for a test drive and my dashboard lit up like a christmas tree (ABS, TSC, TPMS, ACC, ...). The issue was consistently poping up after excedeing 30 km/h. After some research I found that I shouldn't of have sprayed the ABS sensor with brake cleaner, so after confirming the ABS wheel speed sensor fault with VCDS I removed the sensor. After measuring the resistance I found that the sensor was dead. Ordered a new sensor (Meyle) and installed it on the bearing. Went for another test drive and the lights did not turn on...until about 70-80-90 km/h. Did another VCDS scan, again a fault on the ABS sensor, but this time it is not showing a mechanical failure, but an intermitent fault. After that I went for a test drive and I graphed all four wheel speed sensor and found that there were periodic dips in speed reading from the left front sensor (picture below). My first suspicion was the wiring, so I tried jacking up the car onto jack stands and tried driving the car on stands towards 100 km/h (I know it is not the best thing to do to the driveshafts). The graph also showed dips when running the car on the jack stands, so this eliminates the effect of bumps on maybe bumping the wiring and creating a short or something of the sort. Does anyone know what to diagnose further? Could it be a bad sensor or a bad magnetic ring on the new wheel bearing? I tried removing the senosr and cleaning the inside of the wheel hub assembly with some cotton swabs, but to no avail. Is this indicative of a bad new sensor or a bad magnetic ring on the new hub (I did not cheap out and bought a SKF bearing). I have ran out of ideas how to diagnose this issue, other than poping in the old bearing and taking it for a spin, but I don't wanna waste another weekend swapping out hubs if it is not necessary. Does anybody have any other suggestions?

 

 

 

 

We've had it on a mini before where we bought cheap hubs and the magnet didn't give a decent pulse to the sensor. 

 

I don't know if SKF are what they used to be any more, or have just become another Eurocarparts "Quality" brand. I normally stick with Febi. 

 

Also, always worth giving the cables down to the sensors a really good check for damage. They can look ok, but have a split in when you flex them about a bit. 

Edited 1 April, 20233 yr by StevesTruck

An update on this topic: I seem to have mangled the ABS magnetic ring when putting the axle back into the bearing housing (the damage was pretty obvious when I removed the bearing assembly). A new bearing assembly did the job.