Dtc P0112 Intake Air Temperature Circuit Low Input

Engine. Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35
3Zr-Fae Engine Control System. Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)

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

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

READ VALUE USING INTELLIGENT TESTER (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

Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.3Zr-Fae Engine Control System.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input
  1. The intake air temperature sensor, built into 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 becomes low, the resistance of the thermistor increases. When the temperature becomes 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, the voltage at terminal THA varies accordingly. 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. Fail-safe mode continues 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. Open in intake air temperature sensor circuit
  2. Intake air temperature sensor (built into mass air flow meter)
  3. ECM

HINT:
When either of these DTCs are output, check the intake air temperature using the intelligent tester. Enter 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

WIRING DIAGRAM


Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.3Zr-Fae Engine Control System.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input


INSPECTION PROCEDURE

HINT:
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 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 INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

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

  1. Read the value displayed on the tester.

    Standard:
    Same as actual intake air temperature.

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


B
Go to step 4

C
CHECK FOR INTERMITTENT PROBLEMS (RAV4_ACA30 RM000000PDQ0T1X.html)
A


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


    Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.3Zr-Fae Engine Control System.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  1. Confirm a good connection at the mass air flow meter.

  1. Disconnect the mass air flow meter connector.

  1. Connect terminals THA and ETHA of the MAF meter wire harness side connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

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

  1. Read the value displayed on the tester.

    Standard value:
    140°C (284°F) or higher.
    Text in Illustration
    *1
    		Mass Air Flow Meter
    *2
    		ECM
    *3
    		Front view of wire harness connector
    (to Mass Air Flow Meter)

  1. Reconnect the mass air flow meter connector.



NG
Go to step 3
OK

REPLACE MASS AIR FLOW METER (RAV4_ACA30 RM000002WQT00SX.html)

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


    Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.3Zr-Fae Engine Control System.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  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:
    Tester Connection
    		Condition
    		Specified Condition
    B1-1 (THA) - B32-87 (THA)
    		Always
    		Below 1 Ω
    B1-2 (E2) - B32-88 (ETHA)
    		Always
    		Below 1 Ω
    Text in Illustration
    *1
    		Front view of wire harness connector
    (to Mass Air Flow Meter)
    *2
    		Front view of wire harness connector
    (to ECM)

  1. Reconnect the mass air flow meter connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)
OK

REPLACE ECM (RAV4_ACA30 RM0000017UO01KX.html)

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


    Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.3Zr-Fae Engine Control System.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  1. Disconnect the mass air flow meter connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

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

  1. Read the value displayed on the tester.

    Standard value:
    -40°C (-40°F)
    Text in Illustration
    *1
    		Mass Air Flow Meter
    *2
    		ECM

  1. Reconnect the mass air flow meter connector.



NG
Go to step 5
OK

REPLACE MASS AIR FLOW METER (RAV4_ACA30 RM000002WQT00SX.html)

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


    Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.3Zr-Fae Engine Control System.Sfi System. Dtc P0112 Intake Air Temperature Circuit Low Input

  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:
    Tester Connection
    		Condition
    		Specified Condition
    B1-1 (THA) or B32-87 (THA) - Body ground
    		Always
    		10 kΩ or higher
    Text in Illustration
    *1
    		Front view of wire harness connector
    (to Mass Air Flow Meter)
    *2
    		Front view of wire harness connector
    (to ECM)

  1. Reconnect the mass air flow meter connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)
OK

REPLACE ECM (RAV4_ACA30 RM0000017UO01KX.html)