E-Bike Repair Online: Diagnose Your E-Bike and Find the Right Part

What you can do online, and what you cannot

Step 1: diagnose your e-bike online in three minutes

Start with the three-minute self-check. It asks three things: does the display light up, does the throttle drive the motor, and is there an error code. Those answers split the bike into short lists of suspects before you spend anything.

• Throttle works, no assist. The fault is isolated to the pedal-assist chain: assist level, brake levers, sensor plug and sensor gap. See pedal assist not working.
• Display lit, motor silent. Check the brake cut-off and the throttle before the controller. See the brake sensor guide.
• Nothing at all. Walk the power-chain checklist.
• Motor moves on its own. Stop riding and remove the battery. Read this first.

Step 2: look up the error code for your display

Code numbers mean different things on different displays, so identify the display family before you read any table. The model is usually printed on the bezel or the back of the housing. If your display shows a code that a manual does not define, treat it as unidentified and diagnose by symptom instead.

Step 3: find the right part online

A part fits only when three layers line up: mechanical (does it mount), electrical (voltage and current) and communication (the controller and display must speak the same protocol). A model name settles none of them. Four photos and one measurement do: the display face, the display connector, the controller label, the motor cable where it leaves the axle, and, for a wheel or motor, the dropout width (135, 170 or 190 mm, and 170 and 190 do not interchange). The four-photo guide explains each shot, and this page shows how to measure.

Find My Part asks about your bike and the fault, then builds a parts list from your answers. The Bike Database records the factory electronics, connector and protocol family for the bike models on file, and flags which rows are still unconfirmed. Then compare e-bike spare parts by connector, pin count and display model, not by bike name. Browse sensors and throttles, wiring and displays directly if you already know the failed part.

One trap worth knowing: a plug that fits and a screen that lights up do not prove the data link works. Only a live speed reading and assist levels that change do. See why a new display may not work with your controller.

Step 4: install it yourself, or take the parts to a local shop

RideRow does not offer on-site or mail-in repair. Installation is done by you or by a technician you choose.

• Doing it yourself. Bench-test the part first (bench-test guide), power down before every plug change, then run the post-install checks, including the brake cut-off. The e-bike repair DIY guide lists the tools and the safety rules.
• Using a local shop. Bring the error code, the display model, your four photos and the part. If a check fails and you cannot find the cause, a local e-bike mechanic can take it from there.

What RideRow does not do

• It does not repair e-bikes, take them in for service, accept mail-in repairs or make house calls.
• It does not sell batteries, and it does not recommend opening, rebuilding or paralleling lithium packs at home.
• It does not decide whether a modification is legal where you ride. Raising current or voltage, or removing a speed limit, can take a bike outside its local e-bike class, and that decision rests with the owner.

To see how the motor, controller and display work together before you order, read E-Bike Components 101.

E-bike repair online: frequently asked questions

Can I repair my e-bike online?

You can diagnose online, but the repair itself is hands-on. Online tools can narrow the fault to one system, decode an error code and identify a matching part. The measuring and the installing still happen at the bike, done by you or by a local technician.

Does RideRow repair e-bikes online or by mail?

No. RideRow does not offer repair, mail-in service or house calls. It sells replacement parts and publishes the guides on this site.

How do I find the right part for my e-bike online?

Identify the display model and connector, read the controller label, count the wires at the motor cable and, if a wheel or motor is involved, measure the dropout width. A model name alone does not tell you whether a part will mount, carry the current or communicate with your controller.

Where do I look up my e-bike error code?

Find your display family first, because code numbers differ between displays. This page links to tables for KT-LCD, SW900, APT and Bafang displays, plus a guide to the 21 to 30 code family that many brands share.

What if the online diagnosis points to the battery?

RideRow does not sell batteries and does not recommend opening, rebuilding or paralleling lithium packs at home. Take the pack to a qualified service point.

Do I need to know my exact bike model?

Not as much as you might think. The display model and its connector matter more than the bike name or the motor wattage; a 500 W bike and a 750 W bike can use the same display.

Last updated: October 2026

RideRow guides, by symptom and system

RideRow's guides, sorted by symptom and system, so you can go from what you see on the bike to the right page without searching. If a guide asks you to unplug anything, switch off and remove the battery first.

Jump to: Error codes and code tables · Won't turn on, won't move or cuts out · Throttle, pedal assist and sensors · Controllers, wiring and conversion kits · Displays and display settings · Hub motors, wheels and fitting · Rad Power Bikes and finding parts · Methods, tools and safe working · Tires, tubes and flats · Riding and ownership basics

Error codes and code tables (18)

A code names a circuit, not a part. Look up the table for your display family and brand, note whether the code is constant or comes and goes, and do the free check it points to before you price anything.

Start here: E-Bike Error Codes: Lookup by Brand and Display

• E-Bike Error Codes 21 Through 30: The Code Family Most Brands Share
• Rad Power Error Codes: The Complete Reference, Updated for 2026
• KT-LCD Display Error Codes: Complete Table and What to Replace
• SW900 Display Error Codes: The Complete Table and What Each One Means
• APT Display Error Codes: One Table Covers 750C, 850C and More
• Bafang Display Error Codes and What They Actually Mean
• Aventon Error Codes: Three Different Systems, One Guide
• Bafang Error 26: What It Points To and What to Check First
• Velotric Error Codes: The Old 21–30 Set and the New E-Series Groups
• Ride1Up Error Codes: What 21, 24, 25 and 30 Mean, Plus the Revv1 List
• Lectric Error Codes Explained: E003, E006 to E011 and HOT on the XP 3.0 and XP4
• Heybike Error Codes E60-E65: What Each Code Means on the Mars 3.0 and Ranger 3.0 Pro
• Lectric E007 Motor Fault: Check the Motor Quick Plug and the Controller Panel Before You Replace Anything
• Lectric E010 and E011 Display Communication Errors: Check the Display Quick Plug First
• Jasion EB7 and X-Hunter Error Codes 21 to 30: What Each One Points To
• Lectric E008 Throttle Fault: The Quick Plug Check, and the XP4 Settings That Mimic a Dead Throttle
• Heybike E65 Motor/Hall Sensor Failure: Testing Before You Buy a New Motor
• Gotrax E-Bike Error Codes: Three Families (E02-E13, Error 21-30 and the Mustang Hex Codes)

Won't turn on, won't move or cuts out (8)

Work out from the symptom where to look before you open anything: nothing on the display, a lit display with no drive, or a bike that cuts out under load are three different searches with different first checks.

Start here: E-Bike Turns On But Won't Move: A Fault-Finding Order

• E-Bike Won't Turn On: The Complete Power-Chain Checklist
• E-Bike Display Won't Light Up: Wiring, Voltage, and When to Replace
• E-Bike Cuts Out While Riding: Battery Sag or Controller Failure?
• The Brake Sensor: The Hidden Cause of "No Power" on E-Bikes
• The 10-Minute Hard Reset That Fixes More E-Bikes Than You Think
• Why Your E-Bike Shuts Off on Hills: Sustained Current, Not Just Voltage
• Super73 Won't Turn On or Keeps Cutting Out: The Connection Checklist Super73 Wants You to Run First
• Rad Power Bike Won't Turn On: A Connector-by-Connector Check Beyond the Battery

Throttle, pedal assist and sensors (7)

Split the problem with the throttle and pedal assist, then test the part that is left. These guides show which reading means a dead part.

• Pedal Assist Not Working But Throttle Works? Try These 5 Fixes First
• Throttle Not Working? Test It With a Multimeter in 10 Minutes
• Cadence Sensor Troubleshooting: Gap, Alignment, and Replacement
• Aventon Pace 500 Throttle Not Working: The Pedal-First Rule, Error 22 and When to Replace It
• Heybike Throttle Not Working: E61, Drive Mode Settings and What to Check Before Replacing It
• Aventon Torque Sensor and Cadence Sensor Replacement: Which Bottom Bracket Fits Which Model
• Rad Power Bikes Throttle Not Working: Test the Throttle and Pedal Assist Separately

Controllers, wiring and conversion kits (14)

Use these to decide whether the controller is really the problem and, if it is, what to read off the old one before ordering: voltage, current, connectors and the display it has to talk to.

Start here: How to Replace an E-Bike Controller: The Full Process

• E-Bike Controller Wiring Color Codes Explained (Phase + Hall)
• Controller, Display, or Both? A Replacement Decision Guide
• Upgrading Controller Amps: What It Costs Your Motor and Battery
• E-Bike Main Wiring Harness: When to Replace It and How to Choose
• Sensorless Controllers: A Fix When Your Hall Sensors Fail
• Bench-Test Your Conversion Kit Before You Install It
• Replacing the Controller on an Older Crystalyte Hub Motor: Wires, Hall Plug, Axle
• After the Install: Power-On Check, Brake Cutoff, and a Careful First Ride
• Bafang OEM Controller Connectors: What Each Plug Is For and the Connection Order in Bafang's Manual
• New Controller Won't Power On? Check the Key Switch Wire First
• Wiring a Headlight to a New Controller: Treat the Light Output as a Signal, Not Power
• Controller Self-Learning Didn't Work? What Each Result Tells You
• Heybike Controller Replacement: Regular Port vs 3C Port on the Mars and Cityscape
• Aventon Controller Replacement: When a Level 2, Aventure or Abound Controller Is the Real Problem

Displays and display settings (7)

Find your display model and protocol from a photo of the screen and its plug; that decides which replacement can work with your controller.

• Why Your New E-Bike Display Doesn't Work With Your Controller
• How to Identify Your E-Bike Display Model (and Why It Matters)
• KT vs No.2 Protocol: Why E-Bike Displays Aren't Interchangeable
• Speedometer Wrong After a Controller Swap? Check Wheel Size and Display Settings First
• KT Display C Parameters: PAS Sensor Type, Current Limit and Low-Voltage Cutoff
• Replacing an Aventon Display: BC147, BC201, BC280 and A280 and Which Bikes Take Which
• Rad Power Bikes Display Showing km/h Instead of mph: Where the Units Setting Is on the Advanced and Integrated Color Displays

Hub motors, wheels and fitting (12)

Decide whether the motor, its cable or something upstream is at fault, then measure the frame before choosing between a motor wheel and a bare hub motor.

Start here: E-Bike Hub Motor Guide: Is It the Motor, Will It Fit, How to Fit It

• Your E-Bike Motor Runs By Itself: Stop Riding and Read This
• Motor Wheel vs Bare Hub Motor: Which Should You Buy?
• Hub Motor Sizing: Dropout Width and Axle Diameter Explained
• Water in the Motor Connector: Inspecting the 9-Pin Plug
• Motor Jerks, Stutters, or Won't Spin: The 36-Combination Fix
• How to Test E-Bike Hall Sensors (and When It Means a New Motor)
• E-Bike Freewheel Removal: Which Tool Fits and What Not to Force
• Hub Motor Axle Washers and Torque Arms: Order, Orientation, and When You Need One
• Thru-Axle Frame? Why a Bolt-On Hub Motor Will Not Fit
• How to Remove and Install a Rear Hub Motor Wheel
• How to Change a Hub Motor: Complete Motor Wheel or Bare Motor
• Hub Motor Cable Torn Off at the Axle? How to Tell If It Can Be Rewired

Rad Power Bikes and finding parts (4)

For Rad Power Bikes owners sourcing parts: what Rad lists today, which models accept aftermarket controller kits, and the photos that confirm a fit.

Start here: Rad Power Bikes Repair: Error Codes, No-Power Checks and Parts

• Rad Power Bikes After the Bankruptcy: Where to Get Replacement Parts Now
• Which Rad Power Models Can Use an Aftermarket Controller Kit?
• 4 Photos We Need to Confirm a Part Fits Your E-Bike
• What Rad Power Still Sells in 2026: Official Spare Parts vs. the Electrical Parts You Have to Source Elsewhere

Methods, tools and safe working (6)

Methods you can follow at home with a multimeter and a phone camera, before you decide what to buy.

• Five Multimeter Measurements Every E-Bike Owner Should Know
• The Minimal-System Method: Find Any E-Bike Fault Without Guessing
• The Two-Bike Cross-Swap Test: Rules, Shortcuts, and One Big Risk
• Best Free Resources to Actually Learn E-Bike Repair
• How to Hold an E-Bike Safely for Repair: Stands, Clamps and Alternatives
• How to Troubleshoot an E-Bike: Free Checks Before Parts

Tires, tubes and flats (3)

Tire and tube guides for e-bikes, with the extra steps a hub motor wheel needs.

• Fat Tire E-Bikes 101: When Do You Actually Need 4-Inch Tires?
• How to Fix a Flat or Change a Tire on an E-Bike
• Inner Tube or Tubeless? Replacing an E-Bike Tire and Tube Together

Riding and ownership basics (4)

Background reading on e-bike classes, riding and battery life.

• Class 1 vs Class 2 vs Class 3 E-Bikes: What the Classes Actually Mean
• Step-Through E-Bikes for Seniors: A Practical Safety Checklist
• Riding an E-Bike to High School: Rules, Parking, and Locks
• How Long Do E-Bike Batteries Really Last (and How to Make Them Last Longer)

Quick-reference pages

• Find your plug: e-bike connector guide
• Measure your dropout width before buying a wheel
• Why your new display doesn't work with your controller (quick reference)
• Motor jerks or won't spin: phase and Hall wiring (quick reference)
• E-bike motor runs by itself: stop riding
• Pedal assist not working but throttle works (quick reference)
• E-bike components 101: motor, controller, display and sensors
• Bike database
• Diagnose your e-bike in three minutes

This list covers the 83 guides published up to November 4, 2026. RideRow sells replacement parts and publishes how-to guides; it does not repair bikes. Brand and model names identify the bikes each guide covers and do not imply any affiliation.