2003 Polaris 3 PRO X Factory Service Manual, Page 281Get this manual
ELECTRICAL Exhaust System Temperature sender440 Pro X
Temp sender The temp sender that is on the 440 Pro will read the exhaust temperature and adjust the timing according to the temperature rangeTo Test the sensor: Unplug sensorAt room temperature the temperature sender will have HIGH resistance (may read Open Line (OL)) depending on your meterAs the pipe gets hotter, the resistance keeps lowering resulting in optimum timing for given RPM and pipe temperature, If the sender resistance is not responding to pipe heat the sensor may need to be replacedLOW PIPE TEMPHIGH RESISTANCE MEDIUM PIPE TEMPMEDIUM RESISTANCE HIGH PIPE TEMPLOW RESISTANCE