The engine coolant water temperature sensor is located in the engine coolant passage of the cylinder head. It detects the water teperature and relays signals to the ECM. It employs a thermistor, which is sensitive to changes in temperature. The electric resistance of a thermistor decreases in response to temperature rise. The ECM judges engine coolant temperture by the sensor output voltage and provides optimum fuel enrichment when the engine is cold.
When idling speed is not appropriate or blacksmoke arises it is likely to be a defect of water temperature sensor.
Refer to P0117, P0118 DTC inspection procedures.
Remove the water temperature sensor from the engine coolant passage of the cylinder head.
With the temperature sensing portion of the engine coolant temperature sensor immersed in hot water, check resistance.
WTS sensor (check pin : terminal 1 and 2)
Temperature (°C) | Resistance (kΩ) |
-40 | 48.14 |
-20 | 14.13 ~ 16.83 |
0 | 5.790 |
20 | 2.31 ~ 2.59 |
40 | 1.148 |
60 | 0.59 |
80 | 0.32 |
100 | 0.19 |
110 | 0.14 ~ 0.15 |
120 | 0.1163 |
Gauge nuit (check pin : terminal 2 and 3)
Temperature (°C) | Resistance (kΩ) |
60 | 125 |
85 | 42.6 ~ 54.2 |
110 | 22.1 ~ 26.2 |
125 | 15.2 |
If the resistance deviates from the standard value greatly, replace the sensor.
Apply aealant THREE BOND TB 2403 or equivalent to threaded portion.
Install water temperature sensor and tighten it to specified torque.
Tightening torque
20 ~ 40 N·m (14.75 ~ 29.50 Ib·ft)
Connect the harness connector securely.
After running engine, check coolant leak.
