Rad Power Bikes RadRunner 1, 2 and Plus: error 24 or assist level 2 flashing

Your RadRunner turns on, but the motor won't push, or it stutters, and the display shows error 24. On bikes with Rad's LED display there is no number: instead, pedal assist level 2 flashes. Rad's error 24 troubleshooting guide says the code often indicates a motor hall fault and covers both displays. This page applies that guide to the RadRunner 1, RadRunner 2 and RadRunner Plus, using Rad's RadRunner connector check guide for where the motor connector sits. The short answer: reseat the motor connector, run Rad's two tests, and send the results to Rad support. If the connector is clean, the cause is most likely the motor cable, a hall sensor inside the motor, or the controller.

Most likely cause

Hall sensors inside the rear hub motor tell the controller where the motor is in its rotation. If one signal drops out at the connector, along the cable, or at the sensor, the controller can't time the motor and flags error 24. EM3EV's hall sensor testing guide lists the typical signs: jerky starts, stutter at low speed, a motor that only runs after the wheel is already rolling, or no motor while the display works.

Other causes to rule out

• A loose, wet or dirty motor connector. Rad's guide checks this first. (Rad error 24 guide)
• A damaged motor cable near the axle, for example after a wheel removal or a fall. (EM3EV)
• A phase wire fault, which Rad codes as error 23. (Rad error 23 guide)
• A controller fault. (EM3EV)

How to confirm

1. Turn off the bike, remove the battery and press the power button to drain leftover power. (Rad)
2. Trace the cable from the rear motor to its connector on the left chain stay, where Rad's RadRunner guide shows the motor cable exiting. (RadRunner guide)
3. Pull the connector straight apart, no twisting. Check inside for moisture, dirt or damage. Photograph anything you find.
4. Reconnect with the internal notch, pins and outside arrows lined up, pressing straight together.
5. Reinstall the battery and turn it on. Rad's guide describes the switch position as "On, Locked".
6. Throttle test: with the rear wheel off the ground on a stand or with a helper holding the bike, turn the bike on and gently twist the throttle. Rad notes that 2019 and earlier bikes need the throttle's own power button pressed first, while 2020 and later bikes have the throttle live when the bike is on. Watch whether the wheel turns.
7. Rollback test: in an open area, with the bike on, roll it backward while quickly and gently twisting the throttle on and off, and note whether the motor pushes. This is Rad's own test from the error 24 guide.
8. Send your results and photos to Rad Product Support for next steps.

Fix options

Reseat or clean the motor connector (easy)

If grit or a loose fit was the problem, this clears it. Replace any zip ties you cut.

Replace the motor cable or hall sensors (pro, needs soldering and electrical experience)

Fixing a damaged hall wire or sensor means opening the hub, removing the stator and soldering in a new sensor, the process Grin Technologies outlines in its hub motor hall sensor replacement guide. This is shop work and only worth it once outside checks point inside the motor.

Swap in a new motor wheel (moderate)

Replacing the whole rear motor wheel is often simpler than opening the motor. Rad's RadRunner rear wheel removal video shows the wheel coming out. Rad's RadRunner 2 replacement parts page did not list a motor or controller when we checked, so ask Rad support for the right part for your year.

Replace the controller (pro)

If a known good motor still shows error 24, the controller is the next suspect. Leave it to Rad or a shop.

Parts

• Zip ties
• Rear motor wheel or motor cable, through Rad support
• Controller, only if a pro confirms it

Videos

When to get a pro

Get help if the connector is wet, burned or damaged, the code returns after a clean reseat, or the tests point to the motor or controller. See motor cuts out and when to call a pro.

Sources

• error 24 troubleshooting guide, support.radpowerbikes.com
• RadRunner connector check guide, support.radpowerbikes.com
• Rad error 23 guide, support.radpowerbikes.com
• hall sensor testing guide, em3ev.com
• hub motor hall sensor replacement guide, EBIKES.CA
• RadRunner 2 replacement parts page, radpowerbikes.com
• RadRunner rear wheel removal video, youtube.com

Stuck after these checks? Find a shop near you.