Rad Power Bikes Radster, RadWagon 5 and RadExpand 5 Plus: error 21 or 23 after climbing hills

You're climbing a long hill, maybe with cargo, and your Radster, RadWagon 5 or RadExpand 5 Plus cuts power and the color display shows error 21 or error 23. Error 21 is abnormal motor current, and the controller has shut the bike down (Color Display error code table). Error 23 is a motor phase fault, an abnormal current pattern that can come from heavy heat during hill climbing or from a faulty controller. The short answer: power down and let it cool. If the code keeps coming back when you are not climbing, it is a fault for Rad support.

Most likely cause

Heat and load. Pulling hard for a long time makes the motor and controller run hot and draw high current. Rad's fix for error 21 is to power down for a while so the motor cools, and for error 23 the same, with a support call if it happens away from hills. (Rad code table)

Other causes to rule out

• A motor phase wire or connector problem. The code often points to the motor phase wires, so check the motor connector for moisture, dirt or damage (error 23 guide).
• Error 12, motor stall, appears when the throttle is applied but the motor can't turn, for example on a steep hill or with the brakes on. Restart, and don't use the throttle in place of the brakes. (Rad code table)
• A faulty controller, if error 23 shows on flat ground. (Rad code table)

How to confirm

1. Note the code and what you were doing: climbing, carrying weight, hot day, or flat and easy.
2. Power off and let the bike rest before trying again.
3. If it returns, power off, remove the battery and drain power. Find the motor cable on the chain stay and unscrew the connector where it has a collar (Radster and RadWagon 5, see the Radster and RadWagon 5 guides).
4. Pull it straight apart and check for moisture, dirt or damage. Reconnect with the pins and arrows lined up.
5. Ride on flat ground at a gentle pace. If 23 appears there, stop and contact Rad Product Support.

Fix options

Let it cool and change how you climb (easy)

Rest the bike, use lower gears and pedal along on long climbs so the motor isn't doing all the work, and avoid holding the throttle against a stall.

Reseat or clean the motor connector (easy)

Clears a dirty or loose phase connection. Photograph any damage for support.

Motor or controller repair (pro)

Repeated error 23 away from hills points to the motor wiring or controller. Replacing a motor cable, motor wheel or controller is work for Rad or a shop. Work inside a hub motor means removing the stator from the hub (Grin), which is not a home job.

Parts

• Zip ties
• Motor wheel, motor cable or controller, only as Rad support directs

When to get a pro

Contact Rad support if error 23 shows on flat ground, if either code keeps returning after cooling, or if the motor connector is damaged or shows heat marks. See motor cuts out and when to call a pro.

Sources

• Color Display error code table, support.radpowerbikes.com
• error 23 guide, support.radpowerbikes.com
• Radster, support.radpowerbikes.com
• RadWagon 5, support.radpowerbikes.com
• Grin, EBIKES.CA

Stuck after these checks? Find a shop near you.