Minor bugs are fixed quickly
E-bikes have now come of age and have left many of their teething problems behind them. If you do encounter a glitch, minor electrical issues can often be sorted out simply by restarting the bike. More serious faults are now the absolute exception, even in our day-to-day testing. If one does occur, it’s best to visit your dealer if in doubt. - Adrian Kaether, Test & Technology Editor
System restart
Trivial, but tried and tested: switch it off and on again. Resetting the system by restarting it can fix minor faults and bugs. E-bikes are no exception. This also recalibrates the entire sensor system. This often gets the e-bike up and running again. If that doesn’t work, a forced system restart – by removing and reinserting the battery – can sometimes help. It’s best to check the contacts on the battery and frame at the same time. There should be no visible signs of water or corrosion on the contacts. If in doubt, clean them. Professionals use contact spray for loose contacts, at the very latest when they get home.
Check the speed sensor
The e-bike switches on as normal, but isn’t providing the correct assistance? In the past, with the old spoke magnet and external speed sensor, problems with the speed signal from the rear wheel were a regular occurrence. The reason is this: technically speaking, the e-bike is a pedelec and is only permitted to provide assistance up to 25 km/h. If the motor does not receive a valid signal from the rear wheel’s speed sensor, it must switch off the assistance.
Therefore, check the magnet on the spoke or brake disc, as well as the speed sensor and connecting cable in the chainstay. Modern Bosch motors rely on a rim magnet, which is often attached to the valve and is detected directly by the motor. It must not be forgotten after changing the inner tube, otherwise the e-bike will not work properly.
It’s particularly common to forget the rim magnet after changing the rear tyre. The result: no motor assistance, or only sporadic assistance.
Check the connecting cable
Particularly following serious falls, but also simply over time, the plug connections on the e-system can come loose. The display, handlebar remote and other components, such as the speed sensor (see above), are connected to the motor and battery via cables. These cables are often simply plugged in. If you’re experiencing problems with the drive system, it’s therefore worth checking the external cabling of the various components in particular. Signs of chafing also indicate faults and faulty connections. If cables or connectors are completely faulty, the only solution is often to visit your dealer. However, this remains the absolute exception in everyday use.
Read out the fault code
Many electric motors can identify the problem and relay this information to the user via an error code. The error code is displayed either on the display itself via coloured LEDs or via the app associated with the system. It aids diagnosis and often makes it easier to pinpoint the problem. For example, error 503 in Bosch systems or W101 in Shimano systems indicates a problem with the speed sensor. Excessive heat in the drive system, a faulty plug connection and many other issues can also be diagnosed straight away. The easiest way to find out exactly what the error code means is to look it up online – provided you have a mobile data connection.
Connect the app
The range of features offered by modern e-bike apps is constantly expanding. Apps have long since become useful diagnostic tools and can even install new software. The hurdle is almost always the same: download the app, create an account. All of this can be a bit of a nuisance when all you really want to do is go for a cycle. However, modern e-bike apps also offer many additional features, such as navigation or fitness tracking. What’s more, they can sometimes be used to fix faults. For example, if the fault is caused by components running different firmware versions. You can then install the latest firmware on all components over the air, thereby fixing certain bugs.
Fully charge the bike
In rare cases, plugging in a charger or fully charging the battery may also resolve the fault. Apart from the few mechanical problems mentioned, faults with e-bikes are often digital in nature. If restarting the bike does not help and there is no app available, you can try plugging in the charger. It communicates with the battery. In exceptional cases, this can resolve problems specifically related to the battery software. If you want to be on the safe side, let the battery charge fully. Then take it for a test ride. If the fault persists, a visit to the dealer will be unavoidable.
Is none of this helping?
In our experience, the six steps outlined above can resolve 90 per cent of all e-bike ‘faults’. Nevertheless, there may of course be more serious problems that cannot be easily sorted out. We’ve seen it all, from broken cables and faulty batteries or controllers to truly bizarre problems, such as a magnetised chainring interfering with the motor’s magnetic field. If in doubt, the only solution is to visit a specialist dealer to get to the bottom of the problem.
At a glance: Roadside assistance for e-bikes
- Restart the system; if necessary, reinsert the battery
- Check the speed sensor
- Check the connection cables to the display and other devices
- Read out fault codes
- Connect the app
- Fully charge the bike
Adrian Kaether
Editor