Bafang BBSHD Pedal assist (PAS) won't work after controller replacement

[tomaszchrapek]

Hi guys, I'd really use some help with this problem. Recently I needed to swap controller on my Bafang BBSHD mid drive e-bike due to error 30 of unknown nature.
Connected the new replacement from ALiexpress no problem and tested with throttle OK.
After I assembled all the components back on the frame and went on a ride the grim reality settled in - I couldn´t use PAS any more (but throttle worked normal as before).
Now, I use 52V battery pack and the original controller was 30A but the new one seems to be only 28A.
Also, I did reprogram my controller using program cable to run PAS without speed limit but it didn't change the fact that pedal assist is no more.
All the other indicators seem to be ok (speed while riding, power provided, speed sensor light).
I double-checked the wiring and connectors inside the controller for any clams or chaffs.
I don't use gear-shift sensors, brake sensors or light cables.
On the old controller I did around 1500km and it died after I was doing maintenance and a spark of static electricity jumped from the screwdriver to the frame.

At this point I'm kind of lost and as fun as riding throttle-only might seem, I'd really like to spin pedals and have that e-bike grin on my face again

 

[fechter]

I would first double check all the PAS settings in the software and compare to a known good set of parameters.

The other thing you can do is to check the PAS signals. The PAS sensor goes to the black 4 wire connector. The grey and white wires are the signals. Measuring the signals is a bit tricky as there is no place to make contact. You could try to dig some of the potting out of the connector and back probe, or you could use a sharp probe and pierce the insulation on the wires. The signal wires should alternate between around zero volts and around 5v as you turn the crank. If either signal is not present, the PAS won't work.

Before poking holes in the wires you might also just try unplugging and reconnecting the PAS connector in case there was a little debris making it lose contact.