Speedo correction

Is there any know speedo issues with these cars? Mine is 4 mph off on the gauge but reads correctly when hooked up to my scan tool (on the scan tool display, not the gauge).

What car do you have? They may have some error because of production tolerances. If you have the reluctor style VSS, the computer can be programmed to correct for tire size, and gear ratio. As the tires wear, the accuracy will vary. If you have the geared style of VSS, the accuracy will depend on the correct gearing of the VSS in relation to the tires and gears. All speedos show an approximation of the actual speed at a given time. There are pulse width modifiers that hook up between the VSS output, and the speedo to correct for discrepancies. Once installed, the selection of switch positions will correct the readout on the speedo.

71novaguy wrote:

Is there any know speedo issues with these cars? Mine is 4 mph off on the gauge

4mph at what speed?

It's a 96 rmw. It is off at all speeds. I believe the gauge is wrong because the scan tool shows mph slower, it cuts off at 112 not 108, and the signs that show you speed always say I'm going slower than what my car shows

I have the exact same problem. Odometer is correct, verified on multiple trips + GPS and mile marker readings.

All the GPS signals on multiple devices show 4mph off at all speeds.

Looking for a solution like OP.

You would have to rotate the entire speedometer motor to achieve that change. Moving the pointer does not seem to change the readout.

PFM,....