Problem · Bafang DP E170 / E180 / E181 Display

E-Bike Speedometer Shows 0 (Bafang E170 / E180 / E181)

Causes + how to fix it

Quick answer

The display shows 0 or the wrong speed. Most likely cause: a speed magnet that has moved or fallen off, a damaged sensor cable, or a wrong wheel-size setting. Try this first: turn it off and on again.

Try this first

Free, and each takes under 5 minutes.

Turn it off and on again
Check the speed sensor magnet

In plain English

The display works out your speed from a sensor, either inside a hub motor or a separate sensor and spoke magnet, plus the wheel size you've set. If it shows 0, the signal isn't arriving. If it shows the wrong speed, a setting is usually wrong. On many bikes, a missing speed signal also cuts the motor's help.

Step-by-step checklist

Work from the top. Steps go from free and easy to shop jobs. Switch the bike off before touching any connector. Tick each step as you go. Your progress is saved on this device.

1Turn it off and on againFree Switch the display off, wait 30 seconds, then switch it back on. If the code clears, note what you were doing when it appeared, in case it comes back.
2Check the speed sensor magnetFree Find the small magnet on a spoke (or on the brake rotor) and the sensor on the frame it passes. Make sure the magnet is still there, hasn't slid along the spoke, and passes close to the sensor. Your manual gives the exact gap.
3Check the wheel size settingEasy In the display's settings, make sure the wheel size matches the size printed on your tire (for example 26, 27.5 or 29 inches). A wrong setting makes the speed read too high or too low.
4Check the speed sensor cableEasy Switch off. Follow the thin cable from the speed sensor to its plug. It often runs near the chain or rear wheel, where it can get cut. Pull the plug apart and push it back together firmly.
5Unplug and check the motor connectorEasy Switch off and remove the battery. Follow the motor cable to its plug (often near the rear axle or under the frame). Pull it apart, look for bent or pushed-back pins, water, corrosion or burn marks, let it dry, then push it back together firmly.
6Have the sensor replacedShop job If the sensor is damaged or still faulty after these checks, a shop can test and replace it.

Parts you might need

As an Amazon Associate I earn from qualifying purchases. These links go straight to Amazon.

Only buy a part if the free steps didn't fix it. Always match the voltage and connector type to your bike.

Speed sensor and spoke magnet
Replaces a lost magnet or damaged speed sensor. Match your motor system.
Link coming soon
Electrical contact cleaner spray
Cleans dirt and corrosion from connector pins and battery contacts.
Link coming soon

Still not fixed?

Pages to try next:

When it's time for a shop: if you've worked through every step and the problem is still there, take the bike to an e-bike shop. Bring your notes on when it happens, plus the code.

Words on this page: PAS (pedal-assist sensor)Speed sensor