[greywolf]

I take it you tried swapping the STPS and TPS because you were having a problem. Indications are you had a bad TPS and it is now malfunctioning in the STPS position.

A C28 is caused by the following:

1.When no actuator control signal is supplied from the ECM or
communication signal does not reach ECM or operation voltage
does not reach STVA motor, C28 is indicated. STVA can not
operate.

2. STVA lead wire/coupler.

A C29 means an STPS problem.

1. The sensor should produce following voltage.
0.1 V sensor voltage 4.8 V
Without the above range for 4 sec. and more, C29 is indicated.

2.Secondary throttle position sensor, lead wire/coupler connection.

 

[v-chops]

Occasionally the bike's been having rough running/no power when returning to idle, for some time and thuoght to swap them over.
#C29 is not lit anymore only C28.
There must be a motor in the STVA, which is going nutzo.
Will get another multimeter and go thru all the checks but unsure if that will help

I put the sensors back to their original positions whit no change to symptoms

 

[greywolf]

I'll bet the old TPS now in the STPS position is driving it crazy. I'd replace it.

 

[p38arover]

It will be interesting, Don, as to the part no. your dealer comes up with. Greywolf pointed out a revised part no. for the TPS but Western Motorcycles (my local dealer) only had the old part no. in their computer. See http://www.stromtrooper.com/698516-post82.html

I was reluctant to buy the old part no. item and will probably wait until I'm in the US next month to buy a new TPS.

 

[v-chops]

Thanks for your input GW, I hope you bear with me and give me guidance. Havn't much time latley.
Should I be able to move the secondary butterflyes freely by hand and how much should they move? The manual (from memory) says to close them but they hardly move, and when I move them slightly the (with ign on) noise stops but returns when I open thm fully.
Night shift tonight but will get to bike tomorrow/monday

 

[greywolf]

I think it's like this. They should move freely with the ignition off. With the ignition on, the motor should position them. I'm not even close to certain though.

 

[v-chops]

It's been a while but the problem is now fixed :hurray:
I checked with multi meter as much as I could handle mentally :headbang:, just seemed to going round in circles. The best I could work out (guesstimate) is that the actuating motor auto stop was at fault, but not positive. The motor is not a servicable item and I think you have to buy a whole new throttle body to replace the motor :furious:
I decided to just keep riding with the FI light on and the secondary throttle butterflies wound fully open (this stopped the actuating motor from running full time), not ideal but kept me rollin' along. A pending trip of 2 weeks far from home had me take the bike to a local mechanic, who was a former service manager with the local dealer. Telling him of the symptons he said that this problem used to occur in some GXSR'r and that he could repair the actuating motor, :thumbup:. Pick the bike up that afternoon $190 total cost, gotta be happy with that.