Error C28

[Notty]

A very good friend of mine has a K3 which is showing Error C28 and a high tickover - bike has been stood through the winter and was fine before that. so it the STVA , can that be purchased? is it easy to change ? or there are complete K2 throttle assemblies on FleaBay at the moment-which is the best way to go? 

[seth]

Has he tried taking it off and cleaning all the connections (Mark where it is before removal)
If that doesn't work adjust it I'm sure there's info on how to here .
I think you can get replacements but there not cheap .
You might also find Suzuki use the same part on other bikes to give him a better chance of finding one 2nd hand .

[Hooli]

I'd lube the whole thing up with a good spray of WD40 or similar as it's probably just gone sticky over the winter. Follow that by balancing the throttles & then setting both the TPS & the STPS.

That's fixed everyone I've ever seen with this issue.

Obviously if it's sticky then it won't be moving correctly. But the ECU only knows where it's moved by the readings off the two throttle sensors, so they need to bet set correctly which shouldn't be done till the throttles are balanced.

[Andre]

Clean all(!) the connections first, corrosion is the most likely as the bike stood over the winter.
Check for damaged wiring.
C28 doesn't have to be the STVA (yes, electronics can be a bitch). Can't remember the specific cases.
STVA new comes only with full TB assembly. All TBs (K2-7) can be used if you need to look at fleabay, wrecker.
There are repair options, sure someone will chime in here what can be done.

[seth]

Just checked Robinsons and both sensors are available as spares
1 is approximately  £127 the other is around £100 .
As already said check clean and adjust every thing first
Good luck

[Notty]

Just checked Robinsons and both sensors are available as spares
1 is approximately  £127 the other is around £100 .
As already said check clean and adjust every thing first
Good luck

is the  STVA part number 13580-42F00? if so £83 from Germany incl p & p 
@seth

[seth]

I'm not sure which is which but it's either part 16 or 17 in the drawing attached to this post .

I'd seriously look at trying what others have said before buying these new parts .
Hope you get to the bottom of it .

[Andre]

STVA is not a sensor but the "squarish" actuator in the middle of the TB.

[seth]

My mistake yes if it's that you can't get them as spares but I've not heard of an stva failing .
The butterflies and rest of the throttlebodies will be gummed up after sitting over the winter and in need of a deep clean and check and adjust as hooli has discribed.

[Snapey]

Suzuki will tell you the STVA is not a serviceable part ... it is. The glue holding the magnets are a well known failure. If the chokes don't open & shut freely then my bet is a dislodged magnet. Reach under the right hand side to find the choke shaft. (see photo)

This subject has been well documented so search the archives.

[Hooli]

The STVA is a stepper motor as far as I'm aware if we want to be technical.

I've heard of the glue failing a couple of times before too, but never seen it. I wonder if they used better glue on K2s?

[Snapey]

I've heard of the glue failing a couple of times before too, but never seen it. I wonder if they used better glue on K2s?

The two that I've had go were both K2's. I don't know how common it is on later models but checking the chokes for free movement is the first thing to do if the C28 comes up. If there's any stiffness other than the slight spring pressure then you can bet a magnet has come loose but if it moves freely then start looking at the different sensors.

Picture shows the dislodged magnet. (they should be opposite each other). BTW, I used 24 hour Araldite to re-glue the loose magnet.

[grog]

Thanks Snapey, mines not broken but will file your info. 

[Notty]

Thanks Snapey, she has already paid an *expert* to clean etc - he said its a common fault and needs a new part !! she has got hold of some throttle bodies complete as this is the easiest and cheapest way . Thanks for all the advice guys 

[Snapey]

Thanks Snapey, she has already paid an *expert* to clean etc - he said its a common fault and needs a new part !! she has got hold of some throttle bodies complete as this is the easiest and cheapest way . Thanks for all the advice guys 

I hope she doesn't leave the throttle bodies with the expert as he'll fix them & sell on Ebay. If she doesn't want them I'm sure someone on here would enjoy pulling it all apart & fixing the offending STVA. While it's in pieces I like to flush the injectors too.