SFI SYSTEM, Diagnostic DTC:P0112, P0113
| DTC Code | DTC Name |
|---|---|
| P0112 | Intake Air Temperature Circuit Low Input |
| P0113 | Intake Air Temperature Circuit High Input |
DESCRIPTION
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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).
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The IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
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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.
Tech Tips
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) |
|
| P0113 | Open in intake air temperature sensor circuit for 0.5 seconds (1-trip detection logic) |
|
Tech Tips
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
INSPECTION PROCEDURE
Tech Tips
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.
PROCEDURE
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READ VALUE USING INTELLIGENT TESTER (INTAKE AIR)
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Connect an intelligent tester to the DLC3.
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Turn the ignition switch to ON.
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Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
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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 Tech Tips
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If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
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If there is a short circuit, the intelligent tester indicates 140°C (284°F).
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B 
READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) Click here
C 
CHECK FOR INTERMITTENT PROBLEMS Click here
A 
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READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
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Text in Illustration *1 Manifold Absolute Pressure Sensor *2 ECM *3 Front view of wire harness connector:
(to Manifold Absolute Pressure Sensor)
Disconnect the manifold absolute pressure sensor connector.
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Connect terminals THA and E2 of the manifold absolute pressure sensor wire harness side connector.
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Connect an intelligent tester to the DLC3.
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Turn the ignition switch to ON.
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Turn the tester on.
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Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
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Read the value.
Standard 140°C (284°F) -
Reconnect the manifold absolute pressure sensor connector.
NG
CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM) Click here
OK 
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here
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CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM)
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Text in Illustration *1 Front view of wire harness connector:
(to Manifold Absolute Pressure Sensor)
*2 Front view of wire harness connector:
(to ECM)
Disconnect the manifold absolute pressure sensor connector.
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Disconnect the ECM connector.
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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 -
Reconnect the manifold absolute pressure sensor connector.
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Reconnect the ECM connector.
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE ECM Click here
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READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
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Text in Illustration *1 Manifold Absolute Pressure Sensor *2 ECM Disconnect the manifold absolute pressure sensor connector.
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Connect an intelligent tester to the DLC3.
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Turn the ignition switch to ON.
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Turn the tester on.
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Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.
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Read the value.
Standard -40°C (-40°F) -
Reconnect the manifold absolute pressure sensor connector.
NG
CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM) Click here
OK
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here
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CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM)
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Text in Illustration *1 Front view of wire harness connector:
(to Manifold Absolute Pressure Sensor)
*2 Front view of wire harness connector:
(to ECM)
Disconnect the manifold absolute pressure sensor connector.
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Disconnect the ECM connector.
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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 -
Reconnect the manifold absolute pressure sensor connector.
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Reconnect the ECM connector.
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE ECM Click here
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