2003 Girly with coolant temp sensor issues P0118

[Travel-Junkie]

Hi All,

I've been working out some problems that have been ongoing for my bike for some time. I would occasionally have instances where I would stall and run very rough after the bike was warmed up. Engine light had been on for some time. I finally got my self set up with TuneECU. The PO had put a aftermarket exhaust on with out re-mapping. A new map and resetting the TPS seemed to do wonders for inital starting and idle.

However after a short ride i have a P0118 fault for the Coolant Temp sensor (low voltage or short to ground). I should mention my temp gauge is not working or intermittently working..

My questions to those more knowledgeable than I are:
1) is there a way to test the Coolant Temp Sensor?
2) Could this be a wiring problem? If so does the sensor report to the ECU and then the ECU drives the gauge on the dash? or is the gauge a direct indicator of the temp sensor's reading?

-Sam

[Mustang]

you need a new coolant sensor ...................the ecu has no idea how to control the fuel if it doesn't accurately know the engine temp .

[Travel-Junkie]

Thanks Mustang,

I was hoping to know if it was possible to isolate whether this was an issue with the sensor itself or a wiring issue somewhere else? Maybe the only way is to replace the sensor and see if that does it?

Thanks,

Sam

[Sin_Tiger]

I was hoping to know if it was possible to isolate whether this was an issue with the sensor itself or a wiring issue somewhere else? Maybe the only way is to replace the sensor and see if that does it?

The only things you can do, without fancy test equipment, is disconnect both ends of the cable to the sensor and check for continuity and earth faults. Other than that, as Mustang says, a new sensor is your best bet.

Maybe Bixxer can help as I'm not familiar with Girly wiring.

[Bixxer Bob]

The engine temp sensor, air temp sensor and TPS all get a stable voltage from the ECU which then reads the voltage coming back to determine the information. I've attached the entire Triumph test procedure for reference, but it sounds like either you have a short on the return wire back to the ECU (pink with green dash) or the temp sensor is u/s.  To check the sensor, disconnect the pink/green and check the voltage from the now exposed temp sensor pin to ground (not the exposed pink / green connector!!).  The voltage should rise (or fall) steadily as the engine warms up.

As Mustang says, the ECU can't get the fuel right with the temp sensor u/s, it's probably running horribly rich as it'll think it's cold.  As Sin says, a new sensor is a quick fix, but the intermittent gauge reading makes me think wiring might be the problem.

[Travel-Junkie]

Thanks All! I finally got around to taking everything off the bike and double checking all connections. I was getting good readings from the ECU and could see the Temp Rising with the engine on. Test ride went well, although it was short, should have time for a nice long ride this weekend to see how it goes once the engine is warmed up.

Thanks, Sam

[Aaron Ford]

My 99 threw this code due to low coolant.  There was a leak in the radiator that would cause the bike to show dead cold, then overheat.  I would rent a pressure tester and pump the system up to 14 psi and wait.  Your problem may surface.  A bad cap, cracked overflow tank fittings, bad head gasket could be possibilities.  Or your sensor could have checked out. 

Hope you find it,
Aaron