AlexJ Posted May 11, 2019 Report Share Posted May 11, 2019 link g4+ plugin on an r32 gtr currently the factory oil temp sensor is wired to a AN Temp input and works fine. But of course now the factory oil temp gauge doesn't work. i understand that the sensor can be wired to an AN Volt instead and the factory gauge at the same time. Has anyone done this and can share the voltage vs temp calibration? Or can anyone suggest the easiest method to do the calibration? Is there a way to measure the resistance of the sensor/gauge circuit and combine that with the sensor NTC characteristic resistance vs temp curve to calculate the voltage/temp calibration? Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 11, 2019 Report Share Posted May 11, 2019 Assuming the gauge does use a 5V pull-up (some gauges use 12V which is no good for ecu to measure), then it should be possible to share the signal. The main unknown will be the value of the pull-up resistor. I assume since you are using the sensor now you know what calibration curve it has already. So it will just be a matter of looking at the voltage measured by the ECU at some known temp (say room temp 20deg) and calculating the rest from there. Quote Link to comment Share on other sites More sharing options...
AlexJ Posted May 11, 2019 Author Report Share Posted May 11, 2019 Here's the schematic from the FSM. Is this enough to say whether this would be workable? Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 12, 2019 Report Share Posted May 12, 2019 Start by connecting a voltmeter between ground and the signal wire from the gauge (with no sensor connected), this will tell us if it is pulled up to 5V or 12V. Quote Link to comment Share on other sites More sharing options...
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