Bbs01b fault

[jimriley]

I got an e21 code on the screen the other day. Checked sensor clearance, no joy. No flashing red light. The throttle wasn't working but power stayed on.

I have fitted a new speed sensor, nothing has changed. Fault code pops up about a minute after riding, throttle not working from the start. Zero speed shows on screen from the start and stays that way.
I have checked all connections, all ok.

What can I check next? I have a meter and an almost competent brane...

 

[Woosh]

Error 21 is normally speed sensor not working but it could be that the 5V line is not working.
Unplug the throttle and brake sensors first to exclude them from possible causes.

 

[guerney]

Easier to measure if you shove in paperclips.

 

[jimriley]

I fitted a new speed sensor, doubt it's that but I will test old and new. If not that, what else, is the throttle not working a different issue, does that normally cut out if speed sensor is not working?

 

[Woosh]

If the throttle or a brake sensor has a short, the same error will show.

 

[jimriley]

Checked with meter, intermittent 5v feed to the PS. it disappears into the motor. Time to take motor off and check innards??? Is the controller behind the lh cover? what advice?

Of course, I went to get the ebrompton out to go shopping this morning- no power to display!!! Turned out to be a fractured positive feed to the controller from the battery, against the bullet connector. rapidly repaired with soldering iron and heat shrink to strengthen the area. It had been flexing while folding the bike. So what will there third thing be?

 

[saneagle]

Checked with meter, intermittent 5v feed to the PS. it disappears into the motor. Time to take motor off and check innards??? Is the controller behind the lh cover? what advice?

There could be an intermittent short on the 5v somewhere - more likely not in the controller. First, you should check all the other wires that use 5v, like throttle and speed sensor. Have you got water in the throttle?

 

[jimriley]

Found it, magnet fallen off brake lever for magnetic brake sensor - I've fitted magura rim brakes. Still, I found a snick in cover of pedal sensor lead, which was too long anyway, so repaired, soldered and wrapped in glue heatshrink. Pack of magnets ordered! Thanks for help everyone.