Quality of Parts
The above vehicle came to us with a complaint of a growling noise above 50 mph. Nate (my technician) started to test drive the car and only went about a mile to a round-a-bout down the street and noticed a huge shift in the front end while negotiating the turn. Nate brought the car in and lifted it at which time it became overly obvious that the front passenger side bearing was extremely bad. Upon further investigation, he noted that the bad bearing had damaged the reluctor on the CV shaft and the WSS. So I look up the parts, trying to get the best part for the job through my aftermarket vendors, price the repair and sell.
Nate starts the repair, all is going pretty smoothly, should have been a sign maybe. Now after completion of the parts replacement and test drive, we have an ABS light on in the cluster that was not on before. Nate double checked his work and connected a scope to the sensor he had replaced. In hindsight, he likely wishes he'd scoped both sides at this point. The WSS on this car is a two wire sensor, and the waveform we got was a sine wave pattern, seems correct for two wires.
I took a look at the car, because we were not making any headway and sometimes a fresh eye helps. I could see the tooth ring on the replacement cv shaft easy enough, so I compared it with the original, it was considerably different in tooth width and spacing, so I ordered another one, only a different brand, I didn't bother to check both sides signals, my mistake this time, at least the new shaft was the same as the old one. We still had the abs light on, now I had Nate scope both sides simultaneously to see what was different, AWESOME!, one is sine wave, the other is a square wave (original wss), now we can fix it!
Beck/Arnley sensor should have been good in my opinion...ended up with a Standard/BWD and here is the post repair waveform for this interested.
Early application of analog vs digital signal. I’m surprised they used the same connector/sensor etc. Vehicle may have had VSC vs just ABS? Many factors come into play. I have only seen two wire on any and all WSS weather digital or analog. I’m sure ther are exceptions. Great patterns though!!!!!
Only one number came up, just want to show the importance of finding normal/good to have a comparison. Thanks Rick!
Nice catch. It's always nice to see "good" brand" parts causing us headaches.