ECD SYSTEM, Diagnostic DTC:22 (2)

DTC Code DTC Name
22 (2) Radiator Side Engine Coolant Temperature Sensor Circuit Malfunction

DESCRIPTION

The radiator side 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 (See Fig. 1). The radiator side engine coolant temperature sensor is connected to the ECM. The 5 V power source voltage in the ECM is applied to the radiator side engine coolant temperature sensor from the terminal RTHW via a resistor R. That is, the resistor R and the radiator side engine coolant temperature sensor are connected in series. When the resistance value of the radiator side engine coolant temperature sensor changes in accordance with changes in the coolant temperature, the potential at the terminal RTHW also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation.

The radiator side engine coolant temperature sensor controls the radiator fan.

A01BC4QE01
DTC No. DTC Detection Condition Trouble Area
22 (2) Open or short in radiator side engine coolant temperature sensor circuit for 3 sec. or more

  • Open or short in radiator side engine coolant temperature sensor circuit

  • Radiator side engine coolant temperature sensor

  • ECM

WIRING DIAGRAM

A01BDSOE01

INSPECTION PROCEDURE

Tech Tips

If different DTCs that are related to different systems are output simultaneously while terminal E2 is used as a ground terminal, terminal E2 may be open.

PROCEDURE


  1. INSPECT ECM


    1. A01BCNHE05

      Turn the ignition switch ON.

    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Specified Condition
      RTHW (D4-12) - E2 (D4-9) 0.2 to 3.8 V (20°C (68°F))
      RTHW (D4-12) - E2 (D4-9) 0.1 to 1.5 V (80°C (176°F))

    NG

    INSPECT RADIATOR SIDE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS

  2. INSPECT RADIATOR SIDE ENGINE COOLANT TEMPERATURE SENSOR


    1. A01BCQ4E01

      Measure the resistance according to the illustration.

      OK
      The resistance value is within the acceptable range shown in the illustration.

      Note

      In case of checking the radiator side engine coolant temperature sensor in the water, do not allow water to enter the terminals, and after checking, wipe out the sensor.


    NG

    REPLACE RADIATOR SIDE ENGINE COOLANT TEMPERATURE SENSOR

    OK

  3. CHECK HARNESS AND CONNECTOR (ECM - RADIATOR SIDE ENGINE COOLANT TEMPERATURE SENSOR)


    1. A01BBWIE02

      Disconnect the radiator side engine coolant temperature sensor connector.

    2. Disconnect the ECM D4 connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      RTHW (B29-2) - RTHW (D4-12) Below 1 Ω
      E2 (B29-1) - E2 (D4-9) Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      RTHW (D4-12) - E2 (D4-9) 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM