Hi All, Seriously need some help! Bike died whilst riding along, wouldn't restart. Noticed battery drained... Checked the whole thing for shorts - small 20amp fuse pops every time I push the on switch. Do you think my ECU has a serious issue? How can I prove it? I have no access to another ECU and a used one is costly. Thanks!
There's only one ECU on the 2004, it's behind the upper right hand fairing panel as you sit on the bike, but it won't be that blowing a 20A fuse. Can you confirm which fuse it is as it sounds more like a seized fuel pump. You can lift the tank and disconnect the fuel pump supply to prove this.
If you can find the Fuel Cut Off relay (shown in the middle right of the diagram), you can pull the relay to disconnect the supply to the fuel pump, which is easier than lifting the tank. You could also unplug the ECU and see if trying to start the bike blows the fuse, proving that it's not the ECU, but I'm not sure if the bike would turn over.
Possibly not the pump itself then. I can't see which one the PGM fuse is, but I would still remove the pump relay check everything lights up ok. Also, measure for shorts on the 4 wires in the relay holder with the relay removed. Only the brown wire should be short to ground.
I have tried all the above and everything checks out. When removing plugs from the ECU - the one closer to the headlamp causes the fuse to blow. Disconnected both, all is ok - connect closest to the seat, all okay, as soon as plugged in the 2nd, same issue. Driving me nuts
That helps. Is that the grey plug? Grey plug from the ECU feeds the following:- The red diagnostic plug under the seat (only the brown wire should be a short to ground). 2 pin HESD connector. IAT sensor (what ever that is). Indicator relay. The clocks via the yellow/green wire (can't read what it's for). Crank Position Sensor. MAP sensor. Throttle Position sensor. Switch gear on the left hand bar (indicator bar). Basically unplug as much as you can from that list and plug the ECU back in. Then look for shorts on the connectors that you have removed and start plugging the sensors back in. Hopefully the fuse will blow only on one of the sensors or switch gear, indicating where the problem is.
Thanks Muffking, I'll go through the list and double check. Though I think almost all tried. Fatboy, yes correct
This is different to the dwg I have - could you send to [email protected] please? Is this the 2004 model?
The Engine stop relay can be a problem (associated with BAS and Engine stop switch) check you have no melting at the Bas connector to harness and your kill switch is working as it should , also swap your Fan Relay with the Engine stop relay to see if the problem persists
If anyone is electrical here, would be good to know if I can take out the ECU and run some bench tests
There's not a lot you can check on the ECU off the bike ,usually back probing in situ is the only way to check circuits
Done I agree with Fatboy as the ECU controls all the sensors, so it has to be connected for the fault to appear.The only dead test you can do is check only pin 32 (brown wire) is grounded on the grey ECU connector. Basically if you disconnect virtually everything that the ECU feeds then you should be able to put yourself in a situation where the ECU is connected ok and the bike turns on but won't run or turn over. Then you can start connecting things back up until the fuse blows and take it from there. I'd still like to know which the PGM fuse in the diagram is though.
Yes, the fuse shows up in the diagram off the battery, it's not labelled in the diagrams I posted though. That fuse directly feeds the supply side of the switch in the Engine Stop Relay, so an easy check would be to disconnect that relay and plug the ECU back in to test. The Relay when connected and powered on will also feed the fuel cutoff relay, fan relay, purge control solenoid valve, all primary & secondary injectors. It also feeds ECU pins 15, 16 & 29, but only when the relay switch is closed (energised).
