How to Fix E1 / E2 Error Codes on a Cybex Treadmill

If you are the owner of a Cybex treadmill—specifically legacy models like the 425T, 625T, or 770T—seeing an error code flash on the console can be frustrating. Two of the most common codes owners encounter are E1 and E2. While cryptic, these codes almost always point to a specific relationship: the communication between the motor, the speed sensor, and the lower control board.

What do E1 and E2 Mean?

E1 (Speed Range / Stall Error): This typically indicates that the treadmill belt is not moving, or it is moving significantly slower than the console has requested. The lower control board is sending voltage to the motor, but the speed sensor is reporting zero (or very low) RPMs.
E2 (Overspeed Error): This is the opposite. The treadmill detects that the belt is moving faster than commanded, or the control loop has failed, causing the motor to surge. This is a safety shutdown feature.

Step 1: Check the Speed Sensor (Reed Switch)

The most common culprit for both E1 and E2 errors is the speed sensor (often a reed switch) located near the front motor flywheel. This sensor tells the computer how fast the motor is spinning.

Safety First: Turn off the treadmill and unplug it from the wall.
Remove the Motor Cover: Unscrew the bolts holding the front hood in place.
Locate the Sensor: Look for a small black sensor mounted on a bracket near the motor flywheel.
Check Alignment: The sensor must be within 1/8 to 3/16 of an inch from the magnet on the flywheel. If the vibration of running has jarred it loose, it may be too far away to read the magnet (causing an E1 error).
Adjust: Gently loosen the mounting screw and position the sensor closer to the magnet without touching it. Tighten it back down.

Step 2: Inspect the Magnet

Sometimes the issue isn't the sensor, but the target.

Is the magnet still there? On older machines, the magnet glued to the flywheel can crack or fall off. If the magnet is missing, the sensor reads 0 RPM, triggering an E1 error immediately after start-up.
Clean the Magnet: Metal shavings or dust can accumulate on the magnet, disrupting the magnetic field. Wipe it clean with a dry cloth.

Step 3: Check Motor Brushes (E1 Error Focus)

If your Cybex treadmill starts, tries to move, but feels weak or stalls under load (triggering E1), your motor brushes might be worn down.

Locate the Brushes: These are accessed via the two plastic caps on either side of the main drive motor.
Inspect: Unscrew the caps (carefully, they are spring-loaded). Pull out the carbon brush. If it is less than 1/4 inch long, or if the surface is pitted and uneven, they need to be replaced.
Result: Bad connection at the brushes means the motor can't generate the torque needed, leading to a speed mismatch error.

Step 4: The Lower Control Board (MCB)

If the sensor is aligned, the magnet is clean, and the brushes are good, the issue often lies with the Lower Control Board (MCB).

E2 Scenarios: If you hit "Start" and the treadmill belt instantly surges to full speed before shutting down, the MOSFETs on your motor controller have likely shorted out. This allows full voltage to pass to the motor uncontrolled. This requires a board replacement or professional rebuild.
E1 Scenarios: If the board's relay clicks but no voltage goes to the motor, the power section of the board may be dead.

Is it worth repairing?

Cybex parts are premium components. A new MCB can cost between $300 and $600. If your machine is over 10 years old and the running belt is also worn (increasing friction and killing the new board), it might be time to consider a replacement. Below are the current Cybex models that serve as direct replacements for older units.

The Cybex 625T is the standard commercial replacement for many older home units. It retains the rock-solid stability Cybex is known for but features updated diagnostics that make E1/E2 errors far less common.

If you are looking for a machine with a bit more history of durability in high-mileage settings, the Cybex 770T is a heavy-duty option often found in commercial gyms. It uses a high-peak drive motor that is very resistant to the stalling issues that cause E1 errors.

For the ultimate upgrade, the Cybex 70T combines the brand's industrial AC motor (which eliminates the brush wear issue entirely) with a modern touchscreen console.

Step 1: Check the Speed Sensor (Reed Switch)

The most common culprit for both E1 and E2 errors is the speed sensor (often a reed switch) located near the front motor flywheel. This sensor tells the computer how fast the motor is spinning.

Safety First: Turn off the treadmill and unplug it from the wall.

Remove the Motor Cover: Unscrew the bolts holding the front hood in place.

Locate the Sensor: Look for a small black sensor mounted on a bracket near the motor flywheel.

Check Alignment: The sensor must be within 1/8 to 3/16 of an inch from the magnet on the flywheel. If the vibration of running has jarred it loose, it may be too far away to read the magnet (causing an E1 error).

Adjust: Gently loosen the mounting screw and position the sensor closer to the magnet without touching it. Tighten it back down.

Step 2: Inspect the Magnet

Sometimes the issue isn't the sensor, but the target.

Is the magnet still there? On older machines, the magnet glued to the flywheel can crack or fall off. If the magnet is missing, the sensor reads 0 RPM, triggering an E1 error immediately after start-up.

Clean the Magnet: Metal shavings or dust can accumulate on the magnet, disrupting the magnetic field. Wipe it clean with a dry cloth.

Step 3: Check Motor Brushes (E1 Error Focus)

If your Cybex treadmill starts, tries to move, but feels weak or stalls under load (triggering E1), your motor brushes might be worn down.

Locate the Brushes: These are accessed via the two plastic caps on either side of the main drive motor.

Inspect: Unscrew the caps (carefully, they are spring-loaded). Pull out the carbon brush. If it is less than 1/4 inch long, or if the surface is pitted and uneven, they need to be replaced.

Result: Bad connection at the brushes means the motor can't generate the torque needed, leading to a speed mismatch error.

Step 4: The Lower Control Board (MCB)

If the sensor is aligned, the magnet is clean, and the brushes are good, the issue often lies with the Lower Control Board (MCB).

E2 Scenarios: If you hit "Start" and the treadmill belt instantly surges to full speed before shutting down, the MOSFETs on your motor controller have likely shorted out. This allows full voltage to pass to the motor uncontrolled. This requires a board replacement or professional rebuild.

E1 Scenarios: If the board's relay clicks but no voltage goes to the motor, the power section of the board may be dead.

Is it worth repairing?

For the ultimate upgrade, the Cybex 70T combines the brand's industrial AC motor (which eliminates the brush wear issue entirely) with a modern touchscreen console.