Hi Daniel, the sensor you can see by the sparkplugs is the cylinder head temp sensor, it feeds it's info to the engine ECU and it feeds the info to the instrument pod, on your engine it does'nt use a water temp sensor, it just uses the cylinder head temp.
If this sensor was faulty it would normally show up with other faults, like poor starting either hot or cold and it might put on the ECU warning light on the dash, it would also show up on a scan of live data with a diagnostic reader
nigel
February 2010
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