What exactly does the G62 Coolant Temp Sensor do?

kickoutthelights · Nov 26, 2008

So I've had a faulty one for a while. coolant temp on the cluster is pretty normal, but will dip from time to time, maybe once or twice in a workweek (15 mile roundtrip commute), and generally shows that the engine's at normal temp before I would think it actually should be. Commuted with vagcom this morning, and sure enough the needle set itself to 90 Celsius, but vag-com still showed it rising from the 70s to 90.

I have the new sensor (green) at my house, but can't get my fingers in position to remove the old one (v6), and since I've read that it doesn't effect engine performance at all, I haven't really felt overly pressed to get it done.

With that said - is this sensor's sole purpose to give the temp reading to the cluster?

kenblasko · Nov 26, 2008

G62 is the engine coolant temperature sensor. It is not the one for the gauge.

The coolant temperture sender has two identical, independent sensing elements - one for the gauge and one for the ECM. The ECM looks at G62 to determine how much to enrich the fuel/air mixture on startup. Generally, if G62 gets to far out of wack, the car will be hard to start.

The gauge reading has a deadband where the gauge reading will remain rock solid at about 190*F even though the actual coolant temperature fluctuates. This deadband is from about 167*F to 225*F.

deusexaethera · Nov 26, 2008

...which is to say, if the gauge is moving at all once the engine is warm, then the sensor reading must be fluctuating pretty dramatically to move the gauge out of the 170-210degree deadband. The sensor that feeds data to the ECU may or may not be doing the same thing as the gauge sensor, but it would be a good idea to replace it anyway since it shouldn't fluctuate at all.

What exactly does the G62 Coolant Temp Sensor do?

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