Why not just plug it into TuneECU and disable the AI?

 

Two reasons.

1. I don't have tuneECU or a PC laptop.

2. There's something else going on because the dealer informed me that they were unable to communicate with the ECU due to a problem with the ECU, port, or plug. Was this caused by the fried resistor? Who knows.

The bike runs great, but it would be nice to have the ability to use tuneECU or ttp or for the dealer to be able to diagnose future bike problems. But I'm taking one thing at a time and I'd like to replace that resistor first if possible.

 

^ Agree with bluesforchallah - that is the most efficient way to eliminate the error code and light

If you do still want to install a resistor, 470 ohm 1/2 W from Radio Shack will do the job and just solder it to the wires with a piece of heat-shrink over it.

If the original resistor burned up, the PO presumably used a small value resistance with insufficient wattage.
The original thoughts (not mine!) were to use a 50 ohms resistor, close to emulating the current drawn by the solenoid - if 50 ohm is selected that would require about 5W; anything less than that at such a low resistance is why it burns up.
But it is not necessary to have such a low resistance - by picking a larger value, that in turn means a very low wattage can be used.

 

That resistor being blown will have no effect on ability for communication with ECU through the Diagnostic Port

Most likely cause of issue with non-communication with ECU would be Fuse # 2 is blown.

You can't assume the SAI is the reason for the light - but if resistor truly is burned to point of being open circuit, then all you can do is replace it and see if light goes out after three complete warm-up/cool-down cycles, which of course is your only current resource to see if that is indeed the case.

 

After doing a little digging, I found that Forchetto identifies fuse #2 as the ignition switch main feed. The bike is starts and runs fine - could it do that if this fuse were blown?

 

After doing a little digging, I found that Forchetto identifies fuse #2 as the ignition switch main feed....

Dig a little harder - not on your bike.

 

I don't own a shop manual for this bike yet so what exactly does fuse #2 supply?

 

OK, more digging done: fuse 2 is alarm and diagnostic connector. I'm picking the bike up from the dealer tomorrow and we'll see if that fuse is good or not. You'd think it would be the first thing the tech. would check but my experience with dealer service makes me wonder.

 

Update: I went to pick up the bike today and before paying the bill I checked the fuse #2 and it was burnt through. I then asked the tech whether he had checked the fuse and he said he did, but whether he did or not, he didn't catch it. So he put in a fuse, rolled the bike back into the shop, hooked up to his computer and voila: the ecu communicated just fine. I don't know what caused the fuse to blow but it didn't blow again, so that's good news. There's evidence of some water staining under the seat so water might have gotten into the diagnostic plug. His computer showed the code was being caused by the AI system. The resistor that was in there was large - about the diameter of a pencil, an inch or so long, and looked like a ceramic material. It had melted through the heat shrink completely and appeared burnt. It's still on the bike, I haven't had time to remove it or test it. I picked up a small pack of 470ohm .5watt carbon film resistors at radio shack and they're tiny compared to the one that was in there - approx. 9mm long x 2.5mm diameter. I know zip about resistors - this the right type? And also, after the new resistor is installed, when I run the bike through 3 hot/cold cycles, how cold does it need to be? Overnight stone cold or just an hour or two? Thanks for all the advice!

 

when I run the bike through 3 hot/cold cycles, how cold does it need to be? Overnight stone cold or just an hour or two?

On the Bonnie, once the fault has been cleared, the MIL light will go off by itself after 3 cold/warm cycles* of the engine, although the ECM will keep a record of whatever fault has caused it for another 40 cycles. This feature is useful as even if the fault clears and the light goes off you or the dealer mechanic can "interrogate" the ECM later on to find out if there's a failing component or intermittent fault.

* A single warm-up cycle is deemed to have taken place when the following criteria have been met:

- The coolant (the oil on the Bonnies) temperature must be raised to 72C [162F] or more.
-The coolant temperature must have risen by 23C [74F] or more from its start temperature, when 72C [162F] is reached.
- A controlled power-down sequence must take place, i.e. shutting off using the ignition switch.

 

So the dealers computer wasn't capable of disabling the AI as can be done with tune ecu ? THats to bad as there would be no need for fooling with a resistor then .

 

So the dealers computer wasn't capable of disabling the AI as can be done with tune ecu ?

The official factory diagnostic tool can't do that. Emission laws and all that. They can't be seen to contravene regulations.

 

Yes I forgot about those darn pesky emission laws

 

New 470ohm .5w resistor installed, fuse #2 replaced, ran through 3 hot/cool cycles and the check engine light is now off. Thanks to everyone for the help!