Error E4

How to Fix It

1. Power off and unplug the treadmill.

   After an E4 error, power off the machine using the console power button. Unplug from the wall and wait 60 seconds before attempting to diagnose. Never work on the belt or underside while the machine is plugged in.

2. Check the speed sensor and magnet.

   Remove the motor cover (front cover, usually 2–4 screws) to access the front roller and speed sensor. Locate the small magnet on the front roller hub and the reed switch mounted nearby. Ensure the magnet is still attached to the roller and that the gap between the magnet and reed switch is 3–5mm.

3. Check the reed switch wiring.

   Trace the thin wiring from the reed switch to the motor control board. Look for any pinched, cut, or disconnected wire — the wiring often runs in a bundle along the frame. Reconnect any loose connectors.

4. Manually spin the front roller.

   With the machine unplugged, try turning the front roller by hand. It should spin freely. If the roller is stiff or locked, the bearings have failed — this would also explain E4 as the belt cannot reach operating speed.

5. Restart and test.

   After checking and reconnecting the sensor wiring, plug in and restart. Walk on the belt at 1.5 km/h (slow speed) for 2 minutes. If E4 does not return at slow speed but returns at higher speeds, the sensor is working but has a marginal gap — adjust the reed switch position closer to the magnet.