One of our customers was recently asking about Mitsubishi transmission temeperature (ATF) X-Gauge commands published on our website and the changes done to the transmission temperature codes posted on Pajero forums where MTH is changed from 00010001FFD8 to 00010001FFD0.
By changing the MTH from 00010001FFD8 to 00010001FFD0 the users are essentially lowering the temperature reading reported by the ScanGauge by 8 Degrees Celsius. In our opinion this change is probably incorrect. Mitsubishi outlines the AFT gauge as being 1 Degree Celsius per bit with a -40 Degree Celsius offset. The FFD8 portion of the MTH is the -40 offset. By changing it to FFD0 they're making it a -48 Degree Celsius offset. -40 Degrees is a very popular offset to use because it's where Fahrenheit and Celsius are equal to each other, which makes it easier to convert between the two when you get down to the byte level math. Anything is possible though, so testing the different MTH's to see which one is more accurate is always a good step to take if there's any question as to which one is correct.
In conclusion, a good way to test if an X-Gauges MTH is correct is to check if the temperature reading matches up fairly well with the coolant temperature (°cWT) and intake air temperature (°cIA) after the vehicle has sat overnight (overall temperature has had a chance to settle around the ambient temperature).
Once it's sat overnight turn the key to the on position so the electronics are awake to talk to the ScanGauge so AFT, °cWT, and °cIA can be read, but leave the engine off so it doesn't cause everything to warm up. Then compare the AFT reading to the °cWT, and °cIA readings. Whichever MTH results in a AFT value closer to ambient temperature is likely to be the correct one.
You can find Mitsubishi transmission temeprature X-Gauges HERE.