Mph readings on scanmaster

[turbobooster]

What causes the mph readings on the scanmaster 2.1 to not read consistently ? And go to zero out of no where at times?

 

[dand]

If you speedometer needle is working and not jumping around, most likely it is the vss (vehicle speed sensor) going, if you are sporting the stock gauge cluster. It is attached to and located behind the gauge cluster. HTH

 

[turbobooster]

My speedometer needle does jump around but I thought becuz the scan master is hooked up to the ECM it would still read accurately even though the needle doesn't since it's more mechanically driven by the speedo cable ?

 

[RIFF RAFF]

Also

It works on a delay .i notice sometimes it cant keep up and stops working & when i let off the gas it catches up ..

 

[turbobooster]

That's exactly what it does but then just goes zero until I come to a complete stop then it reads for a bit and back to zero so is that normal with these scanmasters?

 

[RIFF RAFF]

No

that's exactly what it does but then just goes zero until i come to a complete stop then it reads for a bit and back to zero so is that normal with these scanmasters?

sounds like a wire or vss for you .id try loose wire first

 

[turbobooster]

Thanx I will look into that where would I find the wires for the vss besides the main connection behind the cluster ? Where can they b loose at?

 

[BlackOut89]

I am having the same issue. I just wired my scan master in and the first thing I noticed was that my MPH readings were off and was reading slow not keeping up with my speed on accel and decel. I have a 145 spedo and thats off as well but I do have bigger tires in the back so I assume that's that cause. Would that make the scan master MPH readings off? Also with the scan master MPH reading lagging could this also mean my other reading could be coming in off or possibly delaid?