ECD SYSTEM, Diagnostic DTC:22 (1)

DTC Code DTC Name
22 (1) Engine Coolant Temperature Sensor Circuit Malfunction

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 (See Fig. 1).

The engine coolant temperature sensor is connected to the ECM. The 5 V 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 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.

A01BC4QE01
DTC No. DTC Detection Condition Trouble Area
22 (1) Open or short in engine coolant temperature sensor circuit for 0.5 sec. or more

  • Open or short in engine coolant temperature sensor circuit

  • Engine coolant temperature sensor

  • ECM

WIRING DIAGRAM

A01BI5BE01

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.

  • Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

When using intelligent tester:

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch ON.

    3. Select the item "Powertrain/Engine and ECT/Data List/Coolant Temp" and read its value displayed on the intelligent tester.

      Result
      Display Proceed
      - 40°C (- 40°F) A
      140°C (284°F) or more B
      The same as actual engine coolant temperature C

      Tech Tips

      When DTC 22 (1) is present, check the engine coolant temperature by selecting "Powertrain/Engine and ECT/Data List/Coolant Temp" on the intelligent tester.

      Temperature displayed Malfunction
      - 40°C (- 40°F) Open circuit
      140°C (284°F) or more Short circuit

    B

    CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS

    A

  2. CHECK HARNESS AND CONNECTOR (CHECK FOR OPEN)


    1. A01BGV7E01

      Disconnect the engine coolant temperature sensor connector.

    2. Connect the terminals 1 and 2 of the engine coolant temperature sensor harness side connector.

    3. Turn the ignition switch ON.

    4. Read temperature value on the intelligent tester.

      Temperature
      140°C (284°F) or more

    NG

    CHECK ECM (CHECK FOR OPEN) Click here

    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR

  3. CHECK ECM (CHECK FOR OPEN)


    1. A01BEQRE02

      Connect between terminals THW and E2 of the ECM connector.

    2. Turn the ignition switch ON.

    3. Read the temperature value on the intelligent tester.

      Temperature
      140°C (284°F) or more

    NG

    REPLACE ECM

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  4. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)


    1. A01BD3GE01

      Disconnect the engine coolant temperature sensor connector.

    2. Turn the ignition switch ON.

    3. Read the temperature value on the intelligent tester.

      Temperature
      -40°C (- 40°F) or more

    NG

    INSPECT ECM (CHECK FOR SHORT) Click here

    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR

  5. INSPECT ECM (CHECK FOR SHORT)


    1. A01BD8EE02

      Disconnect the ECM D4 connector.

    2. Turn the ignition switch ON.

    3. Read the temperature value on the intelligent tester.

      Temperature
      -40°C (- 40°F)

    NG

    REPLACE ECM

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR

When not using intelligent tester:

PROCEDURE


  1. INSPECT ECM


    1. A01BCNHE19

      Turn the ignition switch ON.

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

      Standard voltage
      Tester Connection Specified Condition
      THW (D4-4) - E2 (D4-9) 0.2 to 3.8 V (20°C (68°F))
      THW (D4-4) - E2 (D4-9) 0.1 to 1.5 V (80°C (176°F))

    NG

    INSPECT ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS

  2. INSPECT 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 engine coolant temperature sensor in the water, do not allow water to enter the terminals, and after checking, wipe out the sensor.


    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR

    OK

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


    1. A01BBWIE05

      Disconnect the 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
      THW (D32-2) - THW (D4-4) Below 1 Ω
      E2 (D32-1) - E2 (D4-9) Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      THW (D4-4) - E2 (D4-9) 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM