Dtc P0112 Intake Air Temperature Circuit Low Input


DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING GTS (INTAKE AIR TEMPERATURE)

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

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

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

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - 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, Gdj150,155.1Gr-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, 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 fail-safe mode until a pass condition is detected.

DTC No.
DTC Detection Condition
Trouble Area
P0112
A 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)
  3. ECM
P0113
An open 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)
  3. ECM

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

GTS Display
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 circuit 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.

WIRING DIAGRAM

  1. for Automatic Transmission

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  1. for Manual Transmission

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-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 TEMPERATURE)

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG).

  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.

    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 RM000000PDQ18TX.html)
A


Go to step 3

2.READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  1. Disconnect the mass air flow meter connector.

  1. Connect terminals 1 (THA) and 2 (E2) of the mass air flow meter wire harness side connector.

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG).

  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
    *A
    		for Manual Transmission
    *B
    		for Automatic Transmission
    *1
    		Mass Air Flow Meter
    *2
    		ECM
    *a
    		Front view of wire harness connector
    (to Mass Air Flow Meter)

  1. Reconnect the mass air flow meter connector.

    HINT:
    for Automatic Transmission
    Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly (LandCruiser RM000004NJC03SX.html).


NG
Go to step 3
OK

CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER (LandCruiser RM000000VW603AX.html)

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

  1. Disconnect the mass air flow meter connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-1 (THA) - C35-17 (THA)
    		Always
    		Below 1 Ω
    C33-2 (E2) - C36-4 (ETHW)
    		Always
    		Below 1 Ω
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-1 (THA) - C35-15 (THA)
    		Always
    		Below 1 Ω
    C33-2 (E2) - C35-7 (ETHA)
    		Always
    		Below 1 Ω

  1. Reconnect the mass air flow meter connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM (LandCruiser RM00000329203TX.html)

4.READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  1. Disconnect the mass air flow meter connector.

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG).

  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
    *A
    		for Manual Transmission
    *B
    		for Automatic Transmission
    *1
    		Mass Air Flow Meter
    *2
    		ECM

  1. Reconnect the mass air flow meter connector.

    HINT:
    for Automatic Transmission
    Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly (LandCruiser RM000004NJC03SX.html).


NG
Go to step 5
OK

REPLACE MASS AIR FLOW METER (LandCruiser RM000000VW603AX.html)

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

  1. Disconnect the mass air flow meter connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-1 (THA) or C35-17 (THA) - Body ground
    		Always
    		10 kΩ or higher
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-1 (THA) or C35-15 (THA) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the mass air flow meter connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM00000329203TX.html)