Precor Error Code LS Speed Sensor Signal Missing

Jan 16, 2022

Applies to 9.23, 9.27, TRM211, and TRM200-14 treadmills

Issue symptoms

This error is shown in the console TIME window when the drive motor speed signal is not received from the speed sensor for eight (8) consecutive seconds. When the LS error occurs, the drive motor and lift motor motion stops and the display is blank except for the error display. The treadmill uses a reed switch and two magnets in the drive roller pulley as a speed sensing system.

The most likely causes for this are the speed sensor wiring having an intermittent or open connection, an intermittent or defective reed switch, or bad drive motor brushes. Least likely but possible is a bad upper PCA(Printed circuit assembly)

Troubleshooting steps

1. Check the reed switch wiring and connection to the lower PCA.
2. Check the reed switch using an ohmmeter while rotating the drive pulley. The reed switch will close when a magnet passes in front of it.
3. Replace both drive motor brushes.
4. Substitute a known good upper PCA to determine if the upper PCA is bad.