Hello, i recently purchased a not starting 2015 Street 750. Thought it would be very easy to get it running. I purchased a obd2 connector to read the codes. I use this connector on the EOBD of my car code reader. My scanner can not connect to the ECM. I also purchased a used ECU thinking that it could be the source of my problems. When i remove all the connectors of the ECU the check engine light stays on. When turning the ignition on the ignition relay turns on but the system relay does not engage. I would appreciate some help to get it running again.

 

Since you say it doesn't crank, you need to charge the battery and get it load tested.
I don't know why you bought a code scanner since the bike will read codes through the speedometer. Harley Trouble Codes

 

It reads as if you purchased a non-running motorcycle in south america..Suriname
The 2015 Street 750 does not seem to be a very popular bike on this forum.
Based on the limited information you provided and taking a wild guess that your motorcycle battery has been tested and reported as OK.
Is it possible that problem could be security system related?
Do you have a key fob with a battery inside the fob that has been tested (plastic tape removed).
Obviously the key fob would need to be married to the security module.
I am unaware of a car ECU scanner working on a Harley so take that out of the equation.
I will also take another guess that you are disconnecting battery when addressing the disconnect and reconnect of computer parts.

 

Is there anything in ECU that has to be mated to bike?

Have you put battery on charger and checked with meter? Does it try start if charger on high and left on bike for few minutes?

You may need drawing and meter and check start relay or whatever your bike has.