Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

WATER TEMPERATURE SENSOR (WTS)

Water Temperature Sensor (WTS) installed in the engine coolant passage of the cylinder head detects the engine coolant temperature and emits signals to the ECU. This part employs a thermistor which is sensitive to changes in temperature. The electric resistance of the thermistor decreases in response to a temperature rise (NTC). The ECU determines engine coolant temperature by the sensor output voltage and provides optimum fuel enrichment when the engine is cold.

Circuit Diagram And Output Feature (WTS):

Harness Connector:

SENSOR INSPECTION (WTS)

Using High-Scan (PRO):

1. USING HI-SCAN (PRO)

Using Multimeter:

2. USING MULTI-METER

1. Remove the Water Temperature Sensor (WTS) from the intake manifold.
2. With the temperature sensing portion of Water Temperature Sensor (WTS) immersed in hot engine coolant, check the resistance.
3. If the resistance deviates from the standard value greatly, replace the sensor.

3. USING VOLT-METER

Troubleshooting Procedures:

TROUBLESHOOTING HINTS

If the fast idle speed is not adequate or the engine gives oft dark smoke during warm-up, the Water Temperature Sensor (WTS) might be the cause.

INSTALLATION

1. Apply sealant LOCTITE 962T or the equivalent to the threaded portion.
2. Install the Water Temperature Sensor (WTS) and tighten it to the specified torque.

Tightening Torque : 20 - 40 Nm (2 - 4 kg.m, 14.5 - 28.9 lb.ft)

3. Securely connect the harness connector.