bbshd 750w error 21


New member
Local time
1:33 PM
Jul 30, 2021
Sunderland UK
it seems simple, I swapped the mid drive over to a better spec bike after a year of use on my canndale, its worked great all that time, since i swapped over the error code 21 has come up with a engine symbol, the speedo doesn't work when i check the wheel sensor it flashes as it passes the magnet, I've inspected the cable and that seams fine, not been squashed anywhere, nothing to do with the error but another question,,,,, I'm not bothered if the speedo works, the speed of the power levels has always been to much, especially in the lower levels so I've learned how to change them, will it work ok without the sensor keeping a consistent speed. thanks G
just a update, tested the three wires leading to the wheel sensor, I've got 4.9 from the black and red wire, I've got nothing from the black and white wire, i now know that the problem is with the white wire, looking at that wire it has not been damaged so from there where do I go to try solve this issue with out spending loads money, thanks G