Description And Operation

DESCRIPTION 

• The coolant temperature sensor is used by the Powertrain Control Module (PCM) to calculate the engine temperature.
• To obtain this information it uses the sensor element's ability, as an Negative Temperature Coefficient (NTC) sensor, to vary its resistance according to the temperature.
• The engine temperature sensor is fitted on the thermostat housing.

OPERATION 

• The reference voltage for the NTC element is 5 V; because the Powertrain Control Module PCM input circuit is designed as a voltage divider, this voltage is divided between a resistance in the Powertrain Control Module PCM and the NTC resistance in the sensor.
• The Powertrain Control Module (PCM) can therefore assess sensor resistance changes through voltage variations and thus obtain temperature information.

  Comparative table °C/°F/ohm The indicated internal resistance is the nominal resistance
  °C	°F	ohm	°C	°F	ohm
  -40	-40	48805	50	122	806.9
  -30	-22	27414	60	140	575.8
  -20	-4	15971	70	158	418.1
  -10	14	9620	80	176	308.6
  0	32	5975	90	194	231.2
  10	50	3816	100	212	175.7
  20	68	2502	110	230	135.2
  25	77	2044	120	248	105.4
  30	86	1679	130	266	83.1
  40	104	1152	140	284	66.2