Dtc P0112 Intake Air Temperature Circuit Low Input


DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING GTS (INTAKE AIR)

READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

DTC P0112 Intake Air Temperature Circuit Low Input

DTC P0113 Intake Air Temperature Circuit High Input


DESCRIPTION

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.2Tr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input
  1. The intake air temperature sensor, mounted on the mass air flow meter sub-assembly, monitors the intake air temperature. The intake air temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the intake air temperature is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the ECM as voltage changes (see Fig. 1).
  2. The intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
  3. Resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes according to changes in the intake air temperature, the voltage at terminal THA also varies. Based on this signal, the ECM increases the fuel injection volume when the engine is cold to improve driveability.
    HINT:
    When DTC P0112 or P0113 is stored, the ECM enters fail-safe mode. During fail-safe mode, the intake air temperature is estimated to be 20°C (68°F) by the ECM. The ECM continues operating in fail-safe mode until a pass condition is detected.

DTC No.
DTC Detection Condition
Trouble Area
P0112
Short in the intake air temperature sensor circuit for 0.5 seconds (1 trip detection logic).
  1. Short in intake air temperature sensor circuit
  2. Intake air temperature sensor (built into mass air flow meter sub-assembly)
  3. ECM
P0113
Open in the intake air temperature sensor circuit for 0.5 seconds (1 trip detection logic).
  1. Open in intake air temperature sensor circuit
  2. Intake air temperature sensor (built into mass air flow meter sub-assembly)
  3. ECM

HINT:
When either of these DTCs is stored, check the intake air temperature by entering the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

Temperature Displayed
Malfunction
-40°C (-40°F)
Open circuit
140°C (284°F) or higher
Short circuit

MONITOR DESCRIPTION

The ECM monitors the sensor voltage and uses this value to calculate the intake air temperature. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a malfunction in the intake air temperature sensor and stores a DTC.
Example:
If the sensor output voltage is higher than 4.91 V for 0.5 seconds or more, the ECM determines that there is an open in the intake air temperature sensor circuit and stores DTC P0113. Conversely, if the output voltage is below 0.18 V for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit and stores DTC P0112.
If the malfunction is not repaired successfully, a DTC is stored 0.5 seconds after the engine is next started.

MONITOR STRATEGY


Frequency of Operation
Continuous

CONFIRMATION DRIVING PATTERN

  1. Connect the GTS to the DLC3.
  2. Turn the ignition switch to ON and turn the GTS on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the ignition switch off and wait for at least 30 seconds.
  5. Turn the ignition switch to ON and turn the GTS on.
  6. Wait 5 seconds or more.
  7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
  8. Read the pending DTCs.
    HINT:
    1. If a pending DTC is output, the system is malfunctioning.
    2. If a pending DTC is not output, perform the following procedure.
  9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  10. Input the DTC: P0112 or P0113.
  11. Check the DTC judgment result.

    GTS Display
    		Description
    NORMAL
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment completed
    2. Perform driving pattern after confirming DTC enabling conditions
    N/A
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    HINT:
    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. If the judgment result shows INCOMPLETE or N/A, perform the Confirmation Driving Pattern and check the DTC judgment result again.

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.2Tr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input


INSPECTION PROCEDURE

HINT:
Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
1.READ VALUE USING GTS (INTAKE AIR)

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the GTS on.

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

  1. Read the value displayed on the GTS.

    OK:
    Same as actual intake air temperature
    Result
    Result
    		Proceed to
    -40°C (-40°F)
    		A
    140°C (284°F) or higher
    		B
    Same as actual intake air temperature
    		C
    HINT:
    1. If there is an open circuit, the GTS indicates -40°C (-40°F).
    1. If there is a short circuit, the GTS indicates 140°C (284°F) or higher.


B
Go to step 4

C
CHECK FOR INTERMITTENT PROBLEMS (LandCruiser RM000000VNL00AX.html)
A


2.READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.2Tr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  1. Disconnect the mass air flow meter sub-assembly connector.

  1. Connect terminals 4 (THA) and 5 (E2) of the mass air flow meter sub-assembly wire harness side connector.

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the GTS on.

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

  1. Read the value displayed on the GTS.

    Standard value:
    140°C (284°F) or higher
    Text in Illustration
    *1
    		Mass air flow meter sub-assembly
    *2
    		ECM
    *a
    		Front view of wire harness connector
    (to mass air flow meter sub-assembly)
    HINT:
    Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly (LandCruiser RM000004NJC03XX.html).


NG
Go to step 3
OK

CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER SUB-ASSEMBLY (LandCruiser RM000002VE200IX.html)

3.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

  1. Disconnect the mass air flow meter sub-assembly connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C33-4 (THA) - C154-23 (THA)
    		Always
    		Below 1 Ω
    C33-5 (E2) - C154-31 (ETHA)
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM (LandCruiser RM000000VW203EX.html)

4.READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.2Tr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  1. Disconnect the mass air flow meter sub-assembly connector.

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the GTS on.

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

  1. Read the value displayed on the GTS.

    Standard value:
    -40°C (-40°F)
    Text in Illustration
    *1
    		Mass air flow meter sub-assembly
    *2
    		ECM
    HINT:
    Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly (LandCruiser RM000004NJC03XX.html).


NG
Go to step 5
OK

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY (LandCruiser RM000002VE200IX.html)

5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

  1. Disconnect the mass air flow meter sub-assembly connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C33-4 (THA) or C154-23 (THA) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM000000VW203EX.html)