Hi Bluebee/All ABS Traction experts,
I have been following your thread and work for over a year and many thank for such a wealth of information.
Following my own ABS/traction indicators lighting up on my dashboard and no speedo I followed your thread and played with speed sensors and trying to get a multimeter to work. Eventually I sent off thye module to BBA in the UK as I'm UK based. Following the rebulid everything was good for a few weeks and then it failed again, but initially only once every through weeks. However it got worse through the winter and I now coming up for my MOT (UK vehicle check) which if you have and ABS light on is an automatic fail in the UK.
Given the issues were exactly the same as as previous althougth the speedo now continue to work when the ABS/ASC traction lights trip and my autobox has not flipped into failsafe which happened previously I sent the unit back to BBA under warranty. They say they cannot find fault with it and are returning it to me.
So today I set about testing the pins from the ABS connector. I should point here that my car is a 2001 e39 525SE Touring with ASC which I believe differs from the the US spec cars of that year which I belive are all DSC. In the UK DSC was an optional extra on an SE and only standard on a Sport model I believe. Anywas the point is the ABS module is essentially the same with the same pin locations. The car does have 4 speed sensors, one on each wheel.
Anyway I put a new 9V battery in my DMM and set about the test. Interesting as other have posted the diode test yielded no results at all. Given this has been reported by several others maybe this relates to the tpye and specification of the DMM used my is a cheap one £10. However, setting the unit to 20M ohms I achieved the following readings in one direction only:
Left rear, pins 13 &29: 13.47
Right rear, pins 30 & 31: 13.39
Left front, pins 28 & 12: 16.20
Right Front, pins 15 '& 16: 14.31
While the values differ from others posted Looking at consistency it appears that the Left front is rather higher than the others.
Last year I started removing and cleaning my rear speed sensors and I though on of these was the culprit as the speedo had failed. They were filthy and I cleand both them and the rings with cotton buds but did not touch the fronts.
Now with these readings do you think it is possible that muck alone could affect my reading, or more likly a replacement sensor is needed. My initial thoughts are to remove and clean the front sensors and rings and then see what the reading are before I buy a new sensor.
Interesting I also have a spare rear sensor which reads 12 on the 20M setting, or 1.849 on the 2M ohm seeting on the DMM again in one direction only.
Any thoughts/cpmments much appreciated!