The speedometer may become inoperative due to a failed vehicle speed sensor (VSS), . A failed sensor will require replacement.Google+
Car Problem Reports
Plymouth Grand Voyager Speedometer Not Working Due to Failed Vehicle Speed Sensor
Plymouth Grand Voyager Problem
Average Mileage: 193,500 mi (123,000 mi - 264,000 mi)
Visitor, 1998 Plymouth Grand Voyager, 123,000 mi
The speedometer and all the dash gauges stopped working intermittently at first, now they have pretty much stopped working at all. Once in a while they will work for a few minutes.