Originally Posted by
Tom H
Hi,
As I understand it, one basic difference between manual and auto trans is that the number of pulses generated per rev of the driveshaft. I believe that the automatic generates 40 pulses where the manual generates 17 (manual is confirmed). I don't have automatic code and am not sure where on this site I could find it. I had a quick look and didn't see much support for the OBDII generation of PCMs. Perhaps someone could send me a pointer...
In a disassembly I was given, the calibration has a named parameter "TOS_Driveshaft_PPR" which I decode to mean "TRANSMISSION OUTPUT SHAFT PULSES PER REVOLUTION". This name seems almost correct but: The config constant becomes the denominator in a FDIV instruction with a value of $4888. Pushing through all the math I believe this constant is as follows:
("TRANS OUTPUT SHAFT PULSES PER REVOLUTION" / "NUMBER OF SECONDS IN A MINUTE) X 2^16
IN NUMBERS
(17 / 60) * 65536 = 18,568 OR $4888 (This is the constant in my code)
-Tom