Topic: VSS signal?

[firebrick43]

My new to me 91 YJ was taken care of fairly well.  But there was a few small things that need attention that I have fixed. 

Any way, it runs good, is getting good gas milage(20-21mpg) and I am fairly happy with the performance but its getting the 4.0 throttle body tomorrow. 

For my question.  The check engine light is not coming on but when I flash the codes, other than the standard 12/33/55, I get 15 which is the VSS signal.  Since my jeep is a 91 it has the cable to the Speedometer as well so it still works.  Does the ECM actually use the VSS signal for the fuel injection maps?  Or do they use it just to turn on that stupid maintenance minder light?  If they don't use it for the fuel maps then I am leaving it alone. 

Thanks

[TrailsLessTaken]

Yeah the PCM uses it, if you find a new one post up the part number cause I need one also, just havent really looked to hard for one yet

[Bounty Hunter]

Yes, it needs the signal.  I had no signal from my VSS for a while and the jeep wanted to die at a stoplight.  Got the speedo working and problem went away.