2009 xb12 scg ecm smoking

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jdweinberger

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Joined
Jul 21, 2023
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hey guys, Im obviously new here. I was riding my bike to work and it randomly shut off on me. the starter button did nothing but all the light came on and everything else worked fine. I read all of the forums pertaining to that issue and followed the recommendations.
battery was good, checked my ground cable, replaced the ignition 15a fuse and after I did that I ran into a bigger problem. when I turn the key to the on position, the lights comes on, I can hear everything turn on, cluster is working but without doing anything else and within seconds of turning the key, the ecm begins to smoke and crackle and burn the plastic! I'm assuming a short somewhere but where do I even begin? is the issue within the ecm? the start button literally does nothing. in the picture you can see the melted plastic on the ecm. I can't even find this same ecm either.
 
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The 2008-2009 Buell OEM "Race" ECM has the following identifiers on it: Race Use Only etched into top of case cover...Tag # is---M31PA282.

The ECM is powered by a dedicated 10A fuse. The ignition circuitry is powered by a 15A fuse. An ECM with a fatal internal flaw traditionally pops the 10A fuse. There are multiple signs and symptoms of a failing ECM. From your pics and description of the symptoms, it appears this ECM has developed a fatal internal short causing both internal and external damage directly related to a positive current flow short and/or short to ground. Almost guaranteed certainty the ECM is junk. The ECM is an electrical component. Anytime an electrical component begins to pop...hiss...crackle...smoke...melt..it is a major internal short to ground.
The popped 15A ignition fuse is a concern. Before replacing the ECM you absolutely must test the entire electrical system for positive short-to-ground. Do this by removing the ECM and its 10A fuse...replacing 15A ignition fuse...and carefully check entire wiring system front to back. I would specifically concentrate on the dreaded "red run wire" short at the steering neck main harness...and all the wiring looms and connectors under the seat.
If you find by removing the ECM unit and its companion 10A fuse, the ignition circuitry and its 15A fuse return to normal with no shorts, then it's likely the ECM was somehow back-feeding into the ignition circuit causing that dedicated fuse to pop.

Lastly, when all this is resolved and bike operational again....ABSOLUTELY TAKE A VOLTAGE READING at the battery terminals to insure a faulty VR pumping massive voltage into the system isn't causing all these problems. Correct voltage at a fully charge battery with clean tight terminals should be 13.4 to 14.5 volts DC @ 2500RPM
 

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