DTC 22

Data Trouble Code No. 22 - Engine Coolant Temperature Signal

Detecting Condition

Open or short in Engine Coolant Temperature Sensor signal for 0.5 seconds or more.

Trouble Area

- Open or short in Engine Coolant Temperature Sensor circuit.
- Engine Coolant Temperature Sensor.
- Engine Control Module.

Malfunction Indicator Lamp

Normal Mode On
Test Mode On

Code 22 Description:

Circuit Description
The engine coolant temperature sensor senses the coolant temperature. A thermistor built into the sensor changes the resistance value according to the coolant temperature. The lower the coolant temperature, the greater the thermistor resistance value, and the higher the coolant temperature, the lower the thermistor resistance value.

Coolant Temperature Sensor Specifications:

The engine coolant temperature sensor is connected to the engine control module. The 5 V power source voltage in the engine control module 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 coolant temperature, the potential at the terminal THW also changes. Based on this signal, the engine control module increases the fuel injection volume to improve driveability during cold engine operation. If the engine control module records the diagnostic trouble code 22, it operates the fail safe function, keeping the coolant temperature at a constant 80°C (176°F).

Code 22 Diagnostic Chart:

Diagnostic Chart

Code 22 Wiring Diagram:

Circuit Diagram

Code 22 Inspection Procedure:

Inspection Procedure