I've got a 2001 Astro cargo van that I cannot get a working VSS signal to save my life. I went to the ECM, pulled the 'black' connector and found the green wire with white tracer, tapped in and could not get my CCS-100 to work.
After troubleshooting all the other wiring connections & switches that I could without driving I was left with the VSS lead. I checked it on my Fluke ScopeMeter and sure enough, there is no pulse whatsoever. However, the speedometer works perfectly.
For grins I moved my tap to pin 1 on the black connector which also has a green w/white tracer and same thing, just some noise, around 50mV but no pulse with driving. I have verified my tap is good, the continuity is perfect from the ECM to the Molex connector on the CCS-100.
Any ideas??? I'm stumped. I have no pinout for the ECM and Google isn't turning up much either. I've got a 5 hour drive on Monday and sure would like to get this working.
Thanks
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R. Brett Gilbert
Ok, I've got some more info now. I went to my local Chevy dealer and they were able to help some. They gave me pinouts of all the ECM connectors, I found another VSO (vehicle speed output as Chevy calls it) on the Blue connector, pin 15.
However, it appears the pulse may be too fast, On my meter I'm seeing a 150hz around 5mph. If my calculations are correct, thats 108,000 pulses per mile which is way too high.
Should I just give up on the VSS and go with the mag sensor?
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R. Brett Gilbert
FWIW - I finally got it working.
I found on the pinout chart that pin 4 on the black connector is also a VSS output, moving the sensing line to pin 4, dark green wire finally got it working.
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R. Brett Gilbert