My 98 Honda Civic speedometer works intermittently. I have replaced the sensor with another used one but the problem persists. Some times my speedometer will erratically swing up and down while I am sitting still. Can the speed sensor emit a signal to move the speedometer while setting still? I'm wondering if this could possibly be my ECM. Any feedback would be greatly appreciated.

 

It's unlikely the sensor is doing that. Probably the problem is the speedometer head itself. Does the odometer always work correctly?

 

When the speedometer is not working the odometer does not register miles traveled.