08 gsxr 750 code C40 - idle speed controller

i'm getting an error code, C40 on my 08 gsxr 750.

according to the manual, c40 indicates a problem with the idle speed controller(ISC). the spec on the controller is ~80 ohms at 68 degrees. my meter shows 18 ohms at about 50 degrees. i need to check my meter, but it seems apparently to be the cause of the code.

searching on the internet reveals (apparently):
a recall for an ISC for some gsxr 1000's, but are any 08 750's affected by a similar recall ?

a bypassed clutch switch can also cause this. but, my clutch switch and levers are stock, and seem to be working perfectly


any of you guys know the deal ?


thanks


(a good list of links to lots of suzuki manuals
http://foro.gsxr.es/manuales-de-servicio-de-motos-suzuki-gsx-r-t497.html

08 750: http://rapidshare.com/files/275246326/GSX-R750__99500-37140-03E_.pdf.html )

 

There were a handful of guys on GDC with this issue, looks like a few bikes had defective ISC. They got them fixed under warranty.

A few were the clutch switch like you stated. By un plugging the switch, cleaning it and plugging it back in it fixed one or two.

 

thx for the reply. it's easy to get help on which oil to use, or how many master links are req'd, but it's hard to find info for tough problems.

so this was on 750's, right ? on the suzuki site, there is no recall on the 750 ISC, but i suppose that not every warranty item is a recall. i doubt that a dealer is going to do the work under warranty on an 08 bike unless there is some tacit understanding that the part is indeed faulty, but just not to the extent of a recall. i suppose it's worth pulling the ISC and looking at it, especially because of the questionable ohm reading, making it look as if the servo really is stuck in the wrong position. i checked my meter, it seems fine. good thing they attach the ISC with security torx bolts. wtf.

any further info would be much appreciated. i really don't want to have to disassemble/assemble multiple times.

 

even if your levers are stock the super cheap clutch switch can still be bad. do you still have to squeeze the clutch to start the bike? if no then the switch is bad and the bike thinks the clutch is on all the time. does it start and run? then the idle servo is ok

 

i have to clutch it to start. i removed the servo, it's default with the key off is in the extended position as shown in the manual. the ohm reading is off, manual shows 80 ohms, actual is 19 ohms, but the servo does operate when the key is on. has anyone actually measured the ohms ? both sides are the same, so i'm thinking the manual is wrong, and this is probably a job for using the SDS. also, if the ECM is removed, anyone know how long it retains it's 'known' settings (since clearing the learned value is one of the SDS functions that seems recommended) ? does it have an internal battery ?

 

I have a gsxr1000 (i think 07) in the shop now that I need to diagnose. Intermittently the idle will drop down and the bike will stall. Not all the time but just every once and a while. I haven't even started on it but I will try to let you guys know what I find.

 

I know this is an old thread, I recently have the same issue as the OP I have a 2009 600 I had 20.13 ohms (tested as per manual) I even brought the ISC inside to warm up to room temp to see if it changed the resistance value.

The 08-10 600 and 750 have the same part number and calls for 80 ohms resistance 11-16 have different part numbers and call for 20 ohms

I just purchased a new isc from the dealer and will update with my findings.

The bike will not idle, running so rich it burns your eyes having it running in a garage. You have to continue to blip the throttle to keep it running. Originally I could not get a code to show up, I put it into dealer mode and was able to start the bike keep it running for about a minute and the code showed up on the cluster c40

 

Well just a little update the part number I received from the local dealer 18117-37H01 is the ISC valve for 2008-2010 Gsxr 600/750 and the resistance is 21 ohms between the pins A-B and C-D as per the manual the bike does not run any better this 80 ohm spec in the manual is clearly not correct

 

Jtrudel90
Did you ever get this sorted out?

Regards,
Gerry