hi,need help!bike is 2007 dyna lowrider, ok,after engine was warm the bike developed a slight misfire on the rear cylinder,which gradually got worse( now misfires from startup)checked the obvious,coil,plugs battery,all ok, very weak spark at rear cylinder,the error code is,p1355 rear ignition coil driver high/shorted.any help much appreciated.I live in N.Ireland,so Harley shops very few and far between. Paul

 

Do you have access to a multimeter? Lots of YouTube videos and google hits about checking the coil resistances. It sure sounds like the coil took a dump but better to do some checks instead of throwing parts at the problem. Good luck.

 

thanks for the reply,yep coil was the first thing I checked,because of the error code,coil is ok

 

The coil drivers could be part of the ignition computer or integrated into the coil pack itself. I don't know how Harley implements theirs.

The driver and the coil are two separate parts, electronically.

 

ok,ignition computer,is that the ecm?

 

I believe so. I'm not familiar with EFI Harley specifics. There will be a computer controlling advance, fuel, etc. The likely place to put the driver(s) is there. It could also be inside the coil pack. Anybody know the waveform and voltage output from the ECM to the coil?

 

The coil gets ion sense (knock), coil front and rear fire from ECM. I'd be checking those wires and connector pins if you haven't already. Beyond that you're into the logic of the ECM and sensors, above my pay grade. Start with the obvious, clean and dielectric grease on the connectors, wire damage, etc. And be sure to curse at it.

 

thanks for reply,yep been checking (in between cursing) things like connectors,wiring,all seems fine,bike has only done 8000 miles,anyone know how to check the ecm?

 

Only the dealer is going to be able to check ECM functions. Unless you have an o-scope and know all the outputs and conditions, that is...which is very rare indeed.

 

ok, well that's out for the moment,anything else it could be?