Identification and Detection of Thermistor-Based Water Temperature Sensors 2

① Check the resistance of the water temperature sensor. Turn off the ignition switch, unplug the water temperature sensor connector, and use a high impedance digital multimeter with Ω gear to check the resistance between the two terminals of the sensor connector while driving. Refer to Figure 3, for example, THW-E2 for the Crown 3.0 sedan and B-A for the Beijing Cherokee car. The resistance measurement method is shown in Figure 4. The resistance value is higher at low temperatures and lower at high temperatures, and should be less than 1k Ω when in a hot state.

Remove the water temperature sensor from the engine and place it in the water in a beaker, as shown in Figure 5. Heat the water in the beaker and use a multimeter to measure the resistance between the two terminals at different temperatures. The resistance value should comply with the specified values in Table 1 and Table 2. If the measurement results differ significantly from the values specified in the table, the water temperature sensor should be replaced.

Figure 4 Resistance measurement of water temperature sensor in car Figure 5 Resistance measurement of water temperature sensor at different temperatures  diode

Table 2-1 Resistance values of Beijing Cherokee vehicle thermistor cooling water temperature/intake temperature sensor

Table 2-2 Resistance of Toyota's Cooling Water Temperature/Intake Air Temperature Sensor diode