Purpose of the speed sensor with a stock ECU

I've been preparing for 1st start of my 5.3l with stock ECU and stock rad fans. I've been chatting with my tuner who doesn't think the speed sensor is necessary and is only useful when using aftermarket fans when the ECU is controlling them. Since I'm using stock fans I believe the stock Porsche equipment runs the entire fan operation.

Can anyone say otherwise? It seems like he may be wrong since the TPC swap kit comes with a sensor and reluctor wheel. I'm wondering if anyone can tell me the speed sensor's function? What does the ECU use the speed sensor's data for?

the pcm uses vehicle speed for a ton of calculations the most noticeable thing with no vss is it will hunt or buck at low speed acceleration, and may even stall when coming to a stop or abruptly drop rpm and stall when you push the clutch in.

if your tuner thinks it doesnt need a vss, find a new tuner cause your not going to be happy with the end result. there is a reason tpc and others have gone to the work of making a reluctor wheel and sensor setup to work with a stock ecm, its because the stock ecm cannot operate correctly without it.

Sounds good, thanks! I knew Kent would've had it in there for a reason.

I bought my 948 without a VSS installed. It was very annoying because it would stall all the time coming to a stop. Installed TPC's kit and no more stalling!