Code 21

DESCRIPTION
The engine coolant temperature sensor is installed in the engine coolant passage of the cylinder head. The engine control module judges engine temperature by the sensor output voltage and provides optimum fuel enrichment when the engine is cold.

TROUBLESHOOTING HINTS
If the fast idle speed is not enough or the engine gives off dark smoke during the engine warm-up operation, the engine coolant temperature sensor might be the causes.






CIRCUIT DIAGRAM





INSPECTION USING SCAN TOOL





HARNESS INSPECTION PROCEDURE

COMPONENT TEST PROCEDURE
1. Remove engine coolant temperature sensor from the intake manifold.





2. With temperature sensing portion of engine coolant temperature sensor immersed in hot water, check resistance.
3. If the resistance deviates from the standard value greatly, replace the sensor.

Resistance at Temperature
5.9 Ohms at 0°C (32°F)
2.5 Ohms at 20°C (68°F)
1.1 Ohms at 40°C (104°F)
0.3 Ohms at 80°C (176°F)

4. Apply sealant LOCTITE 962T or equivalent to threaded portion.

5. Install engine coolant temperature sensor and tighten it to specified torque.

Tightening torque 20-40 Nm (14-29 ft lb)

6. Connect the harness connector securely.