DTC    P0112    Intake Air Temperature Circuit Low Input

DTC    P0113    Intake Air Temperature Circuit High Input

for Preparation Click here


DESCRIPTION

A190753E07
  1. The intake air temperature sensor, mounted in 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 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 which is located inside the ECM.
  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 either DTC P0112 or P0113 is set, 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
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 mass air flow meter sub-assembly)
  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 mass air flow meter sub-assembly)
  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


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 sets a DTC.

MONITOR STRATEGY


Frequency of Operation
Continuous

CONFIRMATION DRIVING PATTERN

  1. Turn the power switch on (IG) and wait for 0.5 seconds or more.

WIRING DIAGRAM


A220564E05


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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

1.READ VALUE USING INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. 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.

    OK:
    Same as actual intake air temperature.


    Result 
    Result
    		Proceed to
    -40°C (-40°F)
    		A
    140°C (284°F)
    		B
    Same as actual intake air temperature
    		C

    HINT:
    1. If there is an open circuit, the tester indicates -40°C (-40°F).
    1. If there is a short circuit, the 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)


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


    A194099E32


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)
-
-

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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. 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)



NG
Go to step 3
OK

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY (Click here)  

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
    D5-1 (THA) - D27-116 (THA)
    		Always
    		Below 1 Ω
    D5-2 (E2) - D27-93 (ETHA)
    		Always
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)  

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


    A194323E03

  1. Disconnect the mass air flow meter sub-assembly connector.
    Text in Illustration 
    *1
    		Mass Air Flow Meter Sub-assembly
    *2
    		ECM

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. 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)



NG
Go to step 5
OK

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY (Click here)  

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
    D5-1 (THA) or D27-116 (THA) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)