What are all the functions of the vehicle speed sensor buffer in a 94 GM 4l60E application Can the computer control the transmission without one?

Answer 1

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I cannot answer all your questions, but perhaps I can help due to a recent experience. I recently purchased a 94 Chevy 2500. 305 Engine with same tranny and 4x4. I went to replace a light on the instrument cluster, put it back together and the speedo no longer worked. After many hours of frustration, trips to the parts store, junkyard (for intrument clusters) no one could tell me what the problem was. I looked at a schematic and observed the VSS buffer. I asked many mechanics at all skill levels what the problem could be. None had ever heard of a speed buffer causing such a problem. Some didn't even know what it was. Anyway, I yanked one out of a similar vehicle in the junk yard. They gave it to me free since they never sold one before. Long story short. It fixed the problem. Anyway, my tranny shifted fine even though the buffer was not working properly as I had to drive to the junkyards to try other instrument clusters. I do know that it controls the speedo, odometer and cruise control functions. One would think that the Electronic version of this tranny would need some sort of signal. Perhaps in this case it come from the tach? During my problem my tach. worked fine. I hope this helps. Murphy's friend

Greetings.

The Vehicle Speed sensor sends an AC sine wave to the vehicle speed sensor buffer. From there, the outputed digital square wave goes to the computer (as an input for speed required for shifting), ABS, Cruise control and also the speedometer cluster.

An interruption in any signal would degrade the functions of the above.

So to answer your question--the vehicle would not shift without a VSS buffer or DRAC module. LW