Dtc 23 Air Temperature Circuit Malfunction


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

When using intelligent tester:

READ VALUE USING INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)

READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)

READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM)

READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)

READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM)

When not using intelligent tester:

CHECK ECM

INSPECT INTAKE AIR TEMPERATURE SENSOR

CHECK HARNESS AND CONNECTOR (ECM - INTAKE AIR TEMPERATURE SENSOR)

DTC 23 Air Temperature Circuit Malfunction


DESCRIPTION

The intake air temperature sensor senses the intake air temperature. A thermistor built into this sensor changes the resistance value according to the intake air temperature as shown in the illustration. The resistance value of the intake air temperature sensor is one of the factors used to determine the fuel injection volume.
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

DTC No.
DTC Detection Condition
Trouble Area
23
Open or short in intake air temperature sensor circuit for 0.5 sec. or more
  1. Open or short in intake air temperature sensor circuit
  2. Intake air temperature sensor
  3. ECM

WIRING DIAGRAM


Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction


INSPECTION PROCEDURE

HINT:
  1. If DTCs that are related to different systems are output simultaneously while terminal E2 is used as a ground terminal, terminal E2 may be open.
  2. 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:

1.READ VALUE USING INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

    Result:
    Display
    		Proceed to
    -40°C (-40°F)
    		A
    140°C (284°F) or more
    		B
    The same as actual engine coolant temperature
    		C
    HINT:
    When DTC 23 is present, the type of malfunction can be determined based on the intake air temperature (see below)
    Temperature Displayed
    		Malfunction
    -40°C (-40°F)
    		Open circuit
    140°C (284°F) or more
    		Short circuit


B
Go to step 4

C
CHECK FOR INTERMITTENT PROBLEMS
A


2.READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

  1. Disconnect the I7 intake air temperature sensor connector.

  1. Connect terminals 1 and 2 of the intake air temperature sensor harness side connector.

  1. Turn the ignition switch ON.

  1. Read the temperature value on the intelligent tester.

    Temperature:
    140°C (284°F) or more


OK
REPLACE INTAKE AIR TEMPERATURE SENSOR
NG


3.READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM)


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

  1. Connect between terminals THA and E2 of the ECM connector.

  1. Turn the ignition switch ON.

  1. 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.READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

  1. Disconnect the I7 intake air temperature sensor connector.

  1. Turn the ignition switch ON.

  1. Read the temperature value on the intelligent tester.

    Temperature:
    -40°C (-40°F)


OK
REPLACE INTAKE AIR TEMPERATURE SENSOR
NG


5.READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM)


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

  1. Disconnect the E21 ECM connector.

  1. Turn the ignition switch ON.

  1. 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:

1.CHECK ECM


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    E21-3 (THA) - E21-9 (E2)
    		20°C (68°F)
    		0.2 to 3.8 V
    E21-3 (THA) - E21-9 (E2)
    		80°C (176°F)
    		0.1 to 1.5 V


OK
CHECK FOR INTERMITTENT PROBLEMS
NG


2.INSPECT INTAKE AIR TEMPERATURE SENSOR


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

  1. Measure the resistance of the intake air temperature sensor.

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


NG
REPLACE INTAKE AIR TEMPERATURE SENSOR
OK


3.CHECK HARNESS AND CONNECTOR (ECM - INTAKE AIR TEMPERATURE SENSOR)


    Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.5L-E Engine Control System.Ecd System. Dtc 23 Air Temperature Circuit Malfunction

  1. Disconnect the I7 intake air temperature sensor connector.

  1. Disconnect the E21 ECM connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    I7-2 - E21-3 (THA)
    		Below 1 Ω
    I7-1 - E21-9 (E2)
    		Below 1 Ω
    E21-3 (THA) - E21-9 (E2)
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM