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How can I troubleshoot my speedometer?

Problems with the speedometer are very rare. If you are having issues it is most likely that your signal or ground is bad.

Verify You Have A Good Common Ground
Make sure that your speedo sender and the speedometer have a good common ground. If in doubt, ground them together on a good ground location.

Verify You Have A Good Signal
You can verify your signal by monitoring the pulses that get counted during calibration:

  • Enter calibration mode
  • If you see pulses being counted on the ODO while not moving then you most likely have signal noise. This can be due to a bad sender or wiring.
  • Start driving a measured mile at a steady speed and have someone monitor the pulses that are being counted on the ODO display.
  • If your signal is good you will see pulses count incrementally (not erratic). The pulses will increment at a faster rate the faster you go, so if you drive a steady speed (i.e. 25mph) you should see the pulse count increment at a steady rate. If the pulses increment erratically then you do not have a good signal. Erratic pulse count while driving a steady speed during calibration indicates you most likely have a bad sending unit.

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