Sfi System - P0113

1. Description

2. Wiring diagram

3. Inspection procedure

4. Read value using intelligent tester (intake air temperature)

5. Read value using intelligent tester (check for open in wire harness)

6. Check harness and connector (mass air flow meter - ecm)

7. Read value using intelligent tester (check for short in wire harness)

8. Check harness and connector (mass air flow meter - ecm)

DTC P0110 Intake Air Temperature Circuit Malfunction

DTC P0112 Intake Air Temperature Circuit Low Input

DTC P0113 Intake Air Temperature Circuit High Input

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DESCRIPTION

1. The Intake Air Temperature (IAT) sensor, mounted on the Mass Air Flow (MAF) meter, 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 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).
   
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 any of DTCs P0110, P0112 and P0113 are 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.

HINT:

When any of these DTCs are set, check the IAT by selecting the following menu items on an intelligent tester: Powertrain / Engine and ECT / Data List / Intake Air.

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

Read freeze frame data using an intelligent tester. Freeze frame data record 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. Connect an intelligent tester to the DLC3.

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

3. Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.

4. Read the value displayed on the tester.

   Standard:

   Same as actual Intake Air Temperature (IAT).
   

   Result:

   Temperature Displayed	Proceed To
   -40 °C (-40°F)	A
   140°C (284°F) or higher	B
   Same as actual IAT	C

   HINT:

   1. If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
      
   2. 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 (Click here)

A

1. Disconnect the C26 Mass Air Flow (MAF) meter connector.

2. Connect terminals THA and E2 of the MAF meter wire harness side connector.

3. Connect an intelligent tester to the DLC3.

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

5. Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.

6. Read the value displayed on the tester.

   Standard:

   140°C (284°F) or higher
   

7. Reconnect the MAF meter connector.

OK	CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER

NG

1. Disconnect the C26 MAF meter connector.

2. Disconnect the C20 ECM connector.

3. Check the resistance.

   Standard resistance:

   Tester Connections	Specified Conditions
   THA (C26-4) - THA (C20-65)	Below 1 Ω
   E2 (C26-5) - ETHA (C20-88)

4. Reconnect the MAF meter connector.

5. Reconnect the ECM connector.

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM

1. Disconnect the C26 MAF meter connector.

2. Connect an intelligent tester to the DLC3.

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

4. Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.

5. Read the value displayed on the tester.

   Standard:

   -40°C (-40°F)
   

6. Reconnect the MAF meter connector.

OK	REPLACE MASS AIR FLOW METER (Click here)

NG

1. Disconnect the C26 MAF meter connector.

2. Disconnect the C20 ECM connector.

3. Check the resistance.

   Standard resistance:

   Tester Connections	Specified Conditions
   THA (C26-4) or THA (C20-65) - Body ground	10 kΩ or higher

4. Reconnect the MAF meter connector.

5. Reconnect the ECM connector.

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE ECM (Click here)