[Newlyn48]

Hi every one hope your all well

just wondering if any one can help me out with the famous C28 code on my K6 600

I have had issues with the bike since I bought the bike 5 years ago and still can’t get it sorted.
The butterfly’s stay open and judder slightly when ignition switched on and brings up C28 instantly from ignition switching on before engine is even cranked.

I have changed the throttle bodies twice now with no joy. I have sent the ecu to get tested and came back good.

I have also swopped ecu from another bike as a precaution in case the ecu test was wrong and still the same with a known good ecu

wiring seems fine from the ecu to the motor checked resistance of the motor and checked resistance from the ecu plug to the motor all checks out as it should.

7 ohms resistance to the motor coils from the motor pins and the wiring pins from the ecu through the loom and the motor and that checks out at 7ohms as well. So that check tells me the loom is OK and the motor is OK.

I feel every thing has now been tested and checked that can give the c28 fault.

I’ve now had the original throttle body and 2 used bodies fitted all doing the same and all motors checked and all have the same resistance (7ohms) surely I can’t be unlucky enough to have 3 knackered throttle bodies

If any one has any suggestions that I’ve not tried please let me no.


Thanks in advance Paul

 

[mallood]

You switched throttle bodies including the valve operator or did you put on the old stva?
Could be real bad luck if you did switched TB's with and bad STVA, but just in case, and you can search here to....

 

[Newlyn48]

I changed the whole thing each time so it’s now had 3 different throttle bodies and valve operators on the bike all 3 have all generated he same code. All 3 just make the butterfly’s do the same thing just a little judder

 

[mallood]

Ok, thats indeed a weird problem, but with you having your ECU checked then al that remains is a problem in the wiring, and yes i know, you measured them, but you never know what wires do when there is a litlle movement. The best way would be to hook it up to an obd with the option to test valve movement, and see what it does, then wiglle wires and look again, maybe some one here knows how to hard wire the stva so it gets power to open and close, that means your connecting the stva after all wiring and see if it will work.
Sorry my man, i guess you have to wait for someone to jump in and help you further, there should be ways to test with direct power, and from there you can elliminate certain parts by going a connector further each time. by the way...you having 2 extra TB's, you could test your self with a battery wich terminal opens and closes with some alligator clips.

 

[Newlyn48]

Ok, thats indeed a weird problem, but with you having your ECU checked then al that remains is a problem in the wiring, and yes i know, you measured them, but you never know what wires do when there is a litlle movement. The best way would be to hook it up to an obd with the option to test valve movement, and see what it does, then wiglle wires and look again, maybe some one here knows how to hard wire the stva so it gets power to open and close, that means your connecting the stva after all wiring and see if it will work.
Sorry my man, i guess you have to wait for someone to jump in and help you further, there should be ways to test with direct power, and from there you can elliminate certain parts by going a connector further each time. by the way...you having 2 extra TB's, you could test your self with a battery wich terminal opens and closes with some alligator clips.

Ok, thats indeed a weird problem, but with you having your ECU checked then al that remains is a problem in the wiring, and yes i know, you measured them, but you never know what wires do when there is a litlle movement. The best way would be to hook it up to an obd with the option to test valve movement, and see what it does, then wiglle wires and look again, maybe some one here knows how to hard wire the stva so it gets power to open and close, that means your connecting the stva after all wiring and see if it will work.
Sorry my man, i guess you have to wait for someone to jump in and help you further, there should be ways to test with direct power, and from there you can elliminate certain parts by going a connector further each time. by the way...you having 2 extra TB's, you could test your self with a battery wich terminal opens and closes with some alligator clips.

It’s driving me mad bike works fine as the butterfly’s are in the open position all the time I just hate riding it with the F1 light shining in my eye ha. I’m going to have to get it booked in with a bike mechanic I’m running out of ideas now. And spent a few quid on throttle bodies and getting the ecu tested. Every things been changed now apart from the loom. Like you said it checks out good but can’t be certain it’s passing the power through as it should. I’m not sure if the motor is 12 volt but I believe it’s pulse fed so might do more damage sending 12volt straight to the motor from a battery???

 

[mallood]

You could always try a 9v block battery, just in case....But maybe hold out a litlle longer, there are some verry well versed folks on here that seen almost every problem pass through, maybe one off them could point you in the right direction....if that doesn't work, you can always go to a workshop.

 

[Newlyn48]

You could always try a 9v block battery, just in case....But maybe hold out a litlle longer, there are some verry well versed folks on here that seen almost every problem pass through, maybe one off them could point you in the right direction....if that doesn't work, you can always go to a workshop.

i have booked the bike into workshop for the 6th October hopefully get it sorted. I will keep an eye on here for any suggestions to try. I can always cancel the workshop visit if some one can point me in the right direction. Just hope I don’t need to buy another complete throttle body don’t think I could risk another 2nd hand one now and I don’t want to pay dealer prices.

 

[TheGeek]

Loose connection at the ECM is typical in this situation. And unless that shop has an electronics expert who can troubleshoot this (which is very hard), and correct it (even harder), you're going to be disappointed.

The other thing is a bad sensor. C29 is supposed to be for the sensor. But if it's in range, but sending unexpected data, the logic points to the STVA as the problem. Make sure you test the sensor too.

 

[Newlyn48]

Loose connection at the ECM is typical in this situation. And unless that shop has an electronics expert who can troubleshoot this (which is very hard), and correct it (even harder), you're going to be disappointed.

The other thing is a bad sensor. C29 is supposed to be for the sensor. But if it's in range, but sending unexpected data, the logic points to the STVA as the problem. Make sure you test the sensor too.

Thanks for the advice I will try and get some info on testing the sensor think I have tested that on my original throttle body but not on the last 2 that I have fitted. When you say loose connection at the ECU do you mean the pins in the wiring loom that goes into the ECU. I tried a ECU yesterday from a good working bike even borrowed the ignition barrel so I could run it. That was still the same Instant c28 and no movement. Thanks

 

[TheGeek]

It would be a harness connector issue, not an ECM issue. Do the same test but in reverse. Your ECM and STVA onto an otherwise known good bike. Test your components against a different harness.

 

[Newlyn48]

It would be a harness connector issue, not an ECM issue. Do the same test but in reverse. Your ECM and STVA onto an otherwise known good bike. Test your components against a different harness.

nice one I will try and borrow a bike chances are slim but I will ask around. The bike I used yesterday was being broken. I bought the throttle bodies off it and borrowed the ECU etc. the bike had only done 6k. he sold the loom yesterday I would have borrowed the loom and bought it if needed. Thanks for the reply 👍🏼