DTC 22

CIRCUIT DESCRIPTION
The engine coolant temperature sensor senses the engine coolant temperature. A thermistor built in the sensor changes its resistance value according to the engine coolant temperature.








The lower the engine coolant temperature, the greater the thermistor resistance value, and the higher the engine coolant temperature, the lower the thermistor resistance value.
The engine coolant temperature sensor is connected to the ECM. The 5V power source voltage in the ECM is applied to the engine coolant temperature sensor from the terminal THW via a resistor R. That is, the resistor R and the engine coolant temperature sensor are connected in series. When the resistance value of the engine coolant temperature sensor changes in accordance with changes in the engine coolant temperature, the potential at the terminal THW also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation. If the ECM detects the diagnostic trouble code 22, it operates the fail safe function in which the engine coolant temperature is assumed to be 80°C (176°F).





DETECTING CONDITION AND TROUBLE AREA





DIAGNOSTIC CHART





WIRING DIAGRAM











INSPECTION PROCEDURE

HINT: If diagnostic trouble codes "22" (engine coolant temperature sensor circuit), "24" (intake air temperature sensor circuit) and "41" (throttle position sensor circuit) are output simultaneously, E2 (sensor ground) may be open.