The first time I got error code 503 I just ran out and bought a new speed sensor and put it in. Worked great for almost a year.
I ride in very wet conditions, lots of mud, puddles even some snow. Error 503 came up on a ride so I limped home and psyched myself up to install another sensor. So I unplugged the cable from the the motor itself and noticed it was quite wet. So I dried that off then blew out the socket with an air can(saw quite a bit of water come out) then I left it unplugged overnight. Put it back together and did a 30 km ride in fairly wet conditions and all is good! (So far). This might not solve everyone’s issue but is definitely an easy fix to try first.
picture is with bike upside down
I ride in very wet conditions, lots of mud, puddles even some snow. Error 503 came up on a ride so I limped home and psyched myself up to install another sensor. So I unplugged the cable from the the motor itself and noticed it was quite wet. So I dried that off then blew out the socket with an air can(saw quite a bit of water come out) then I left it unplugged overnight. Put it back together and did a 30 km ride in fairly wet conditions and all is good! (So far). This might not solve everyone’s issue but is definitely an easy fix to try first.
picture is with bike upside down
