Dtc P0112 Intake Air Temperature Circuit Low Input

Land Cruiser URJ200 URJ202 GRJ200 VDJ200 - 1GR-FE ENGINE CONTROL

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

Dtc P0112 Intake Air Temperature Circuit Low Input. 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200
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).
The intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
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 either 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 ConditionTrouble Area
P0112Short in the intake air temperature sensor circuit for 0.5 seconds (1 trip detection logic).
Short in intake air temperature sensor circuit
Intake air temperature sensor (built into mass air flow meter)
ECM
P0113Open in the intake air temperature sensor circuit for 0.5 seconds (1 trip detection logic).
Open in intake air temperature sensor circuit
Intake air temperature sensor (built into mass air flow meter)
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 / All Data / Intake Air.
Temperature DisplayedMalfunction
-40°C (-40°F)Open circuit
140°C (284°F) or higherShort 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.


WIRING DIAGRAM

Dtc P0112 Intake Air Temperature Circuit Low Input. 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

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)

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

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

Read the value displayed on the GTS.

  • OK:
  • Same as actual intake air temperature.
Result
Temperature DisplayedProceed to
-40°C (-40°F)A
140°C (284°F) or higherB
Same as actual intake air temperatureC
  • HINT:
If there is an open circuit, the GTS indicates -40°C (-40°F).
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 ()
A
2.READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)
Dtc P0112 Intake Air Temperature Circuit Low Input. 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the mass air flow meter connector.

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

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

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

Read the value displayed on the GTS.

  • Standard value:
  • 140°C (284°F) or higher
Text in Illustration
*1Mass Air Flow Meter
*2ECM
*aFront view of wire harness connector
(to Mass Air Flow Meter)
NG
Go to step 3
OK
CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER ()
3.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

Disconnect the mass air flow meter connector.

Disconnect the ECM connector.

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

  • Standard Resistance:
  • for LHD
    Tester ConnectionConditionSpecified Condition
    C50-1 (THA) - C45-73 (THA)AlwaysBelow 1 Ω
    C50-2 (E2) - C45-98 (ETHA)AlwaysBelow 1 Ω
  • for RHD
    Tester ConnectionConditionSpecified Condition
    C50-1 (THA) - C46-73 (THA)AlwaysBelow 1 Ω
    C50-2 (E2) - C46-98 (ETHA)AlwaysBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM ()
4.READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)
Dtc P0112 Intake Air Temperature Circuit Low Input. 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the mass air flow meter connector.

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

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

Read the value displayed on the GTS.

  • Standard value:
  • -40°C (-40°F)
Text in Illustration
*1Mass Air Flow Meter
*2ECM
NG
Go to step 5
OK
REPLACE MASS AIR FLOW METER ()
5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

Disconnect the mass air flow meter connector.

Disconnect the ECM connector.

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

  • Standard Resistance:
  • for LHD
    Tester ConnectionConditionSpecified Condition
    C50-1 (THA) or C45-73 (THA) - Body groundAlways10 kΩ or higher
  • for RHD
    Tester ConnectionConditionSpecified Condition
    C50-1 (THA) or C46-73 (THA) - Body groundAlways10 kΩ or higher
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE ECM ()