Chevy K2500 speed indicator shows to much

[Jamal Iqbal]

Hello,

the speed indicator on my 98 Chevy K2500 no longer works. It shows too much. I have already completely replaced the speedometer without success and also the plug of the speed sensor on the gearbox.

 

Does anyone have a tip for me? Is it perhaps the complete speed sensor - see picture?

[richard wysong]

I put a used cluster in my 98 and the speedo was off so they must be calibrated to specific drive trains..If it is doing the same thing with both of them I would suspect the VSS. With a scan tool that does data you can see the speed the PCM sees from the VSS and go from there, if it shows correct on the scanner then it could be a bad PCM or a bad speedometer

[Jamal Iqbal]

OK, thanks for the tip. Since I first replaced the gauge from the speedo and then the complete speedo, it will probably be the VSS.

Or, if the readings are OK, the PCM - thanks.

[Brian Lindsey]

do you have the correct tire size , has rear diff been changed , if not speedo should be with in 5 mph of actual , mine runs 3-4 miles slow

[Jamal Iqbal]

Yes I have the correct tyre size (245/75R 16)
The speedometer goes straight up to 60 mph when starting and then all the way to the stop.

[Jamal Iqbal]

So the best way ist to test the VSS with a scan tool right?

[richard wysong]

yes