Rad Power Bikes RadCity 3, RadCity 4 and RadCity Step-Thru 3: error 30 on the LCD display

Your RadCity 3, RadCity 4 or RadCity Step-Thru 3 shows error 30 on the LCD display and the bike won't ride under power. Rad's RadCity (2016 to 2020) connector guide covers these bikes by name, including the RadCity 3 (2019), RadCity 4 and RadCity ST 3 (2020), and describes error 30 as a communication error. The short answer: a connector is loose, dirty or damaged, or a part plugged into the system has failed. Reseat the three main plugs, then unplug the rest one at a time.

Most likely cause

A communication error means the display and controller have stopped exchanging signals. Rad's guide has you confirm every connector is secure and in good condition, starting with the battery connector, the display connector and the wiring harness connector, because those carry the signals between the handlebar and the controller (Rad guide).

Other causes to rule out

• Dirty or damaged battery or mounting tray contacts, which Rad checks before any plug. (Rad guide)
• A failed part on one branch: the motor, taillights, brake sensors, throttle, headlight or PAS sensor. If the code clears with one unplugged, Rad says that part likely needs replacing. (Rad guide)
• A bike that won't power on at all. Rad's won't turn on guide for external battery bikes uses a 2019 RadCity Step-Thru as its example.

How to confirm

1. Turn the bike off, remove the battery and press MODE to drain leftover power, as Rad says to do before each check.
2. Inspect the battery and mounting tray contacts. If they look fine, refit the battery and test.
3. Battery connector, near the bottom bracket: large, flat on one side with two big prongs. Pull straight apart, inspect, line up the notch and pins, press together and test.
4. Display connector at the handlebar: twist the metal collar to release, pull apart, inspect, then realign and twist to lock.
5. Wiring harness connector near the seat tube: Rad has you turn the handlebar for slack, feed cable into the top of the downtube, remove the rubber grommet at the lower opening and gently pull the connector out. Inspect, reconnect, tuck it back and refit the grommet.
6. Isolation test: unplug one part, refit the battery and power on with it still unplugged. Rad's order is the motor (left chainstay), taillight, second taillight on bikes with a rack (2019 and newer), each brake connector, throttle, headlight and PAS sensor near the bottom bracket.
7. Photograph anything wet, dirty or damaged and send it to Rad Product Support.

Fix options

Reseat the connectors (easy to moderate)

Most of the work is the harness plug inside the downtube. You need flat side cutters, a flat head screwdriver and zip ties, the tools Rad lists.

Replace the part the isolation test points to (moderate, through Rad support)

Throttles, brake sensors, lights and the PAS sensor plug in. Get the right part through Rad Product Support. Never ride with a brake sensor unplugged, since it cuts the motor when you brake.

Replace the harness, display or controller (pro)

If the plugs are clean and no single part clears the code, have a shop or Rad support test the harness, display and controller.

Parts

• Zip ties
• E-bike connectors
• Main cable (wiring harness)
• E-bike display
• Throttle, Brake cutoff sensor or Pedal assist sensor, only the one the test points to
• E-bike controller (pro only)

When to get a pro

Get help for water or burn marks in a plug, bent pins, damaged contacts, a cable you can't free from the downtube without force, or a code that stays after the full check. See Rad Power Bikes error codes, inspect and clean connectors and when to call a pro.

Sources

• RadCity (2016 to 2020) connector guide, support.radpowerbikes.com
• won't turn on guide for external battery bikes, support.radpowerbikes.com

Stuck after these checks? Find a shop near you.