Intermittent crank sensor

[ian slater]

Hi all
I took my carrera vengeance e spec bike into an independent bike shop recently after losing faith in Halfords after countless visits.Anyway i was told the problem was an intermittent crank sensor.I'm not getting pedal assist but when i turn bike upside down and turn pedals i can hear rear motor.I have looked at ecu and noticed the cable that comes out of ecu and plugs into crank sensor cable looked like it had been squashed.I peeled back the black outer casing and the 4 fine individual cables look ok but is it possible that some of the fine strands could have been broke and this is whats causing crank sensor not to function correctly.
Thank you

 

[saneagle]

Hi all
I took my carrera vengeance e spec bike into an independent bike shop recently after losing faith in Halfords after countless visits.Anyway i was told the problem was an intermittent crank sensor.I'm not getting pedal assist but when i turn bike upside down and turn pedals i can hear rear motor.I have looked at ecu and noticed the cable that comes out of ecu and plugs into crank sensor cable looked like it had been squashed.I peeled back the black outer casing and the 4 fine individual cables look ok but is it possible that some of the fine strands could have been broke and this is whats causing crank sensor not to function correctly.
Thank you

It's almost certainly a cable connection issue. It might even be that the cable has been pulled at the sensor, so one of them has broken its connection. The sensor itself is optical, so nothing can go wrong with it, other than after a lot of use in dirty conditions, the dirt can stop it seeing properly, but that wouldn't be intermittent.

 

[ian slater]

Hi Saneagle
Thank you,i have replaced display, ecu, crank sensor and rear motor,am getting 41.3v out of 36v battery so only thing it could be is this cable i think.Would have to cut possible bad bit out and reconnect.Is there an easy way of re-connecting cables back together
Thank yo
Ian

 

[saneagle]

Hi Saneagle
Thank you,i have replaced display, ecu, crank sensor and rear motor,am getting 41.3v out of 36v battery so only thing it could be is this cable i think.Would have to cut possible bad bit out and reconnect.Is there an easy way of re-connecting cables back together
Thank yo
Ian

Why did you replace the sensor? Is the cable OK on the other one? If so, you can swap them over. IIRC, there's a connector at the sensor end that burried in rubber sealant.

 

[ian slater]

Morning Saneagle
Theres a short sensor cable from ecu(this is one that looks squashed)then have other one that plugs into this and fits to crank,i have two and tried both
Thanks
Ian