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VSS Question

Hello,

I have a FiTech Ultimate LS system installed with a ZF-S6-40 manual transmission from a 90s Corvette.  The car is running and everything seems to be working, except the FiTech system is not reading the correct vehicle speed.

The ZF VSS outputs a 4,000 ppm signal and I believe this is the same as a T56.  In the manual transmission settings, if T56 is selected the system reads 1-2 mph at a vehicle speed of 20 mph.  If the T56 option is changed to "other" it always reads 0 mph.  The automatic transmission is also set to "other".

I know the VSS is working correctly because the stock instrument cluster reads the speed correctly.  The wires from the VSS to the ECU have also been checked.  Is there something else in the settings that may be causing this problem?

Thank you.