SFI SYSTEM, Diagnostic DTC:P0112, P0113

DESCRIPTION

• The intake air temperature sensor, mounted on 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 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, 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.

  Tech Tips

  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.

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 circuit 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 less than 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.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.

2. Turn the engine switch on (IG) and turn the Techstream on.

3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

4. Turn the engine switch off and wait for at least 30 seconds.

5. Turn the engine switch on (IG) and turn the Techstream on.

6. Wait 0.5 seconds or more.

7. Enter the following menus: Powertrain / Engine / Trouble Codes.

8. Read the pending DTCs.

   Tech Tips

   
   

   • If a pending DTC is output, the system is malfunctioning.

   • If a pending DTC is not output, perform the following procedure.

9. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

10. Input the DTC: P0112 or P0113.

11. Check the DTC judgment result.

    Techstream Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
    N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips

    
    

    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

12. If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs Click here.

    Tech Tips

    
    

    • If a permanent DTC is output, the system is malfunctioning.

    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (INTAKE AIR)

   
   

   1. Connect the Techstream to the DLC3.

   2. Turn the engine switch on (IG).

   3. Turn the Techstream on.

   4. Enter the following menus: Powertrain / Engine / Data List / Primary / Intake Air.

   5. Read the value displayed on the Techstream.

      OK
      Same as actual intake air temperature.

      Result

      Result	Proceed to
      -40°C (-40°F)	A
      Higher than 128°C (262°F)	B
      Same as actual intake air temperature	C

      Tech Tips

      
      

      • If there is an open circuit, the Techstream indicates -40°C (-40°F).

      
      

      • If there is a short circuit, the Techstream indicates higher than 128°C (262°F).

   
   

   B

   READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS) Click here

   C

   CHECK FOR INTERMITTENT PROBLEMS Click here

   A

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

   
   

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

      

      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)	-	-

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

   3. Connect the Techstream to the DLC3.

   4. Turn the engine switch on (IG).

   5. Turn the Techstream on.

   6. Enter the following menus: Powertrain / Engine / Data List / Primary / Intake Air.

   7. Read the value displayed on the Techstream.

      Standard value
      Higher than 128°C (262°F)

      Tech Tips

      Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly Click here.

   
   

   NG

   CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) Click here

   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.

   2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition E14-1 (THA) - E26-96 (THA) Always Below 1 Ω E14-2 (E2) - E26-118 (ETHA) Always Below 1 Ω

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   REPLACE ECM Click here

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

   
   
   1. 

      Text in Illustration

      *1	Mass Air Flow Meter Sub-assembly
      *2	ECM

      Disconnect the mass air flow meter sub-assembly connector.

   2. Connect the Techstream to the DLC3.

   3. Turn the engine switch on (IG).

   4. Turn the Techstream on.

   5. Enter the following menus: Powertrain / Engine / Data List / Primary / Intake Air.

   6. Read the value displayed on the Techstream.

      Standard value
      -40°C (-40°F)

      Tech Tips

      Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly Click here.

   
   

   NG

   CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) Click here

   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.

   2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition E14-1 (THA) or E26-96 (THA) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   REPLACE ECM Click here