Toyota Vitz/Yaris ,Speedometer not working, ABS light ON - Fixing Wheel bearing problem

I recently had a problem with my toyota vitz KSP-130. 2013 model.


The problem was noise coming from the front wheel on the driver side as it spins.


I thought,the problem might be the bearings going bad so I decided to have it checked and possibly replace the bad wheel bearing. At the garage  the wheel hub was dis-assembled and the culprit was the bearing as i had predicted. I bought a new bearing  which cost me around $45 and it was fixed onto the hub -Using some pressing machine. The whole process was uneventful and took roughly 1 hours and I was ready to go considering that it was a Friday and the following weekend I had lots of errands to run in town.


 The problem started immediately I switched the car ON. The ABS light decoarated my dashboard and stayed there. I loit pwer  steering completely. The speedometer stopped working. I was startled. I had never before experrience such kind of problem. My mechanic thought was that we had tampered with the sensor which is usually situated on the wheel hub and in close proximity to the side walling of the bearing. So his suggestion was to disassembly the whole thing again and check the status of the sensor- We had no tool of checking functionality of the said sensor, so the remedy we can only do is to remove it,clean it by wiping it dry the return it back. Our thinking was that it might have gotten some oil or grease wrapping hence it could not read.


We did this and then assembled it back and the moment of truth was here - We started the car and still the ABS light was still there. power steering was still no there and the speedometer didnt work either.  We were all not sure what happened. The old bearing was damaged beyond repair in the removal process and therefore returning it was not an option. The mechanic even suggested i buy a new sensor and that the one which was there was fault. I was reluctant to take his advice considering that I had driven same car to the garage without any problem except for the annoying noise from the front driver side wheel.


 I left the car at the garage and went home for the night,distressed as you can think.The following morning I was up early having suspended all my weekend plans.We dis-assembled the wheel again,removed the hub and  as a final decision I decided to physically inspect the old wheel bearing versus the new bearing that we  just fitted. There was not much difference except for the very thin blackish coating on the outer walls on the old bearing. The new bearing was shiny with no coating at all. As it would turn out the black coating is a magnetic film and the  sensor  reads from that film through electromagnetic process as the wheel rotates. That is how the speedometer gets to work.


Having noticed this the fix was to get another bearing with same specifications as the old one.It was difficult to find so i decided to buy a full EX-Japan wheel hub with all its components and we fitted this. We started the car and all  problems were gone, The speedometer worked,The power steering returned. For the ABS we had to clear with a scan tool  and the light didnt return afterwards.


The PROBLEM WAS FIXED.


THIS IS MY TAKE AWAYS FROM THIS EXPLORATION



  1. Modern cars use bearings coated with magnetic linings.

  2. It is important to get the correct bearings otherwise  you will end up spending more fixing non existing problem.


 


 


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