4point9

In the LS3 PCM what is the VSS used for and how many pulses to make a mile?

Thanks, Jack

06MonteSS

Vehicle Speed Sensor... used for your speedo, and can also be used by ABS and stability control systems...

the pulses per mile would depend on the cars gearing and tire size...

ssgunny

iTrader: (6)

I think he is looking for what number of pulses per mile the PCM is looking for from the transmission and maybe what is the signal that is being sent to the speedo (if all things were stock on the car such as wheel size, rear gears, etc.).

4point9

Thanks ssgunny and 06MonteSS for the reply. I should have explained a little more, I was looking for what effect the VSS signal has on the engine management system. I am using a 6 speed manual transmission (F40) that puts out 60K pulses per mile. But when I am running at 60 MPH the scanner tells me the PCM has a reading of a little over 30 MPH. Does this effect engine performance. The speedometer is corrected to the correct signal with the use of a Dakota Digital frequency converter for 60K to 4K pulses per mile.

Frost

iTrader: (45)

Although it's not totally a yes or no question, if you aren't having idle or return to idle issues, you should be fine since the PCM actually sees when the car is moving and when it's stopped.

4point9

Frost, thanks for the reply. The engine runs great, I was worried the the speed reference had some effect on the engine management system.

Jack