DTC    P0112    Intake Air Temperature Circuit Low Input

DTC    P0113    Intake Air Temperature Circuit High Input

for Preparation Click here


DESCRIPTION

A132329E01
  1. The Intake Air Temperature (IAT) sensor, mounted on the Manifold Absolute pressure (MAP) sensor, monitors the IAT. The IAT sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the IAT 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 IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
  3. Resistor R and the IAT sensor are connected in series. When the resistance value of the IAT 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 P0112 or P0113 is set, the ECM enters fail-safe mode. During fail-safe mode, the IAT 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
Short in intake air temperature sensor circuit for 0.5 seconds
(1-trip detection logic)
  1. Short in intake air temperature sensor circuit
  1. Intake air temperature sensor (built into manifold absolute pressure sensor)
  1. ECM
P0113
Open in intake air temperature sensor circuit for 0.5 seconds
(1-trip detection logic)
  1. Open in intake air temperature sensor circuit
  1. Intake air temperature sensor (built into manifold absolute pressure sensor)
  1. ECM

HINT:
When any of these DTCs are set, 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)
Short circuit


WIRING DIAGRAM


A201299E01


INSPECTION PROCEDURE

HINT:
Read freeze frame data using an 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)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

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

  1. Read the value.

Standard:
Same as actual Intake Air Temperature (IAT).

Result 
Result
Proceed to
-40°C (-40°F)
A
140°C (284°F)
B
Same as actual IAT
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).



B
Go to step 4

C
CHECK FOR INTERMITTENT PROBLEMS (Click here)
A


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


    A200840E01

  1. Disconnect the manifold absolute pressure sensor connector.

  1. Connect terminals THA and E2 of the manifold absolute pressure sensor wire harness side connector.

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Read the value.

    Standard:
    140°C (284°F)

    Text in Illustration 
    *1
    		Manifold Absolute Pressure Sensor
    *2
    		ECM
    *3
    		Front view of wire harness connector:
    (to Manifold Absolute Pressure Sensor)

  1. Reconnect the manifold absolute pressure sensor connector.



NG
Go to step 3
OK

REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR (Click here)  

3.CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM)


    A200842E02

  1. Disconnect the manifold absolute pressure sensor 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
    B48-4 (THA) - B8-87 (THA)
    		Always
    		Below 1 Ω
    B48-2 (E2) -B8-120 (E2)
    		Always
    		Below 1 Ω

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Manifold Absolute Pressure Sensor)
    *2
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the manifold absolute pressure sensor connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)  

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


    A201300E02

  1. Disconnect the manifold absolute pressure sensor connector.

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Read the value.

    Standard:
    -40°C (-40°F)

    Text in Illustration 
    *1
    		Manifold Absolute Pressure Sensor
    *2
    		ECM

  1. Reconnect the manifold absolute pressure sensor connector.



NG
Go to step 5
OK

REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR (Click here)  

5.CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM)


    A200842E05

  1. Disconnect the manifold absolute pressure sensor 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
    B48-4 (THA) or B8-87 (THA) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Manifold Absolute Pressure Sensor)
    *2
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the manifold absolute pressure sensor connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)