Strange Behavior of Temp Gauge

[FinalImpact]

Something I have seen happen twice now is the engine temp "C" for coolant randomly changes to the Air intake temp while riding. What's even stranger is you can't change it back until the ignition is turned off. And when it does this, the Air Temp is about 10 deg F hotter than before it switched itself and it hardly moves even though the temp is going up and down. I think on both occasions it went to 86 and never moved.

Its an 08 US bike with less than 6000 miles on it. Anyone seen anything like this?
I could be mistaken, but on both instances I was using the full RPM range of the engine. . . :spank:

The bike has no other known issues and runs fine. There are no error codes and I'm likely going to ignore until something else chimes in showing distress. . .

86'd from the coolant temp. . . lol

 

[Motogiro]

It could be moisture internally in the cluster. That moister could provide a bridge and cause a false Hi/Lo state on the internal circuit board. I don't know if you can open the cluster but if I could I would do that with minimum invasion. Blow it out with dry air and reseal the housing with a light coat of RTV silicone.

 

[Evitzee]

I'd leave it alone, it's not hurting anything. It always defaults back to regular mode when the ignition is turned off so that is why that is happening. Sounds like you have an issue either with a piece of material under the button or moisture which is causing it to change the mode. Unless you feel real handy breaking into the module I'd ignore it. It may eventually go away.

 

[LeaN69]

I've had this happen on my 09 couple of times 2-3. It reset by itself back to normal after I turned the bike off and back on.

 

[FinalImpact]

OK - so another bike or two may be doing this. I guess I'm not alone. . .

For now, I'll likely leave it alone. If anything does change, I'll grab my DMM and confirm the the two inputs to the ECU are reporting good temp values.

Perhaps a bad temp sender is causing a strange reading or as said the buttons have moisture under them? I have seen moisture in the cluster on one occasion so it may have issues creating a need for me to crack it open.

 

[FinalImpact]

Interesting:
Looking at the schematic the TPS, Coolant and Air temp sensors all have a common wire Black/Blue going to the ECU. However, none of these link directly to the cluster.

Looking at the cluster; as best i can tell, the ECU and the cluster share a wire for the coolant and air temp, likely speed and RPM too, hence the the name "Multi-function meter". So it looks to be single multiplexed data signal on the Y/L (Yellow Blue wire) from the ECU send all signals over a single wire and the cluster displays some things all the time, and then the user selects coolant or air temp. But likely both signals are present on a single wire to the cluster.

In short, there are not enough wires to the cluster for all things so some are shared. . . but I could be mistaken. . . So I'll hope that fault is in the cluster and not the ECU! :thumbup: