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
| *1 | Resistance |
| *2 | Acceptable |
| *3 | Temperature |
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The intake air temperature sensor, mounted on the mass air flow meter, 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).
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The intake air temperature 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 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 any of DTCs P0112 and P0113 are 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) |
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| P0113 | Open in intake air temperature sensor circuit for 0.5 seconds (1 trip detection logic) |
|
Tech Tips
When any of these DTCs are output, check the intake air temperature by entering the following menus on the intelligent tester: Powertrain / Engine and ECT / Data List / Intake Air.
| Temperature Displayed | Malfunction |
|---|---|
| -40°C (-40°F) | Open circuit |
| 140°C (284°F) or higher | Short circuit |
WIRING DIAGRAM
| *a | Intake Air Temperature Sensor (Built into MAF Meter) |
CAUTION / NOTICE / HINT
Tech Tips
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 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 TEMPERATURE)
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Connect the intelligent tester to the DLC3.
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Turn the ignition switch to ON and 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 displayed on the tester.
Standard Same as actual intake air temperature. Result Result Proceed to Temperature displayed is -40°C (-40°F) A Temperature displayed is 140°C (284°F) or higher B Temperature displayed same as actual intake air temperature 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) or higher.
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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 Mass Air Flow Meter *2 ECM *3 Front view of wire harness connector
(to Mass Air Flow Meter)
Confirm good connection at the mass air flow meter.
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Disconnect the mass air flow meter connector.
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Connect terminals THA and ETHA of the MAF meter wire harness side connector.
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Connect the intelligent tester to the DLC3.
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Turn the ignition switch to ON and 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 displayed on the tester.
Standard 140°C (284°F) or higher. -
Reconnect the mass air flow meter connector.
OK
REPLACE MASS AIR FLOW METER Click here
NG
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CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
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Disconnect the mass air flow meter 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 B2-1 (THA) - B39-87 (THA) Always Below 1 Ω B2-2 (E2) - B39-88 (ETHA) Always Below 1 Ω -
Reconnect the mass air flow meter connector.
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Reconnect the ECM connector.
OK
REPLACE ECM Click here
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)
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READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
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Text in Illustration *1 Mass Air Flow Meter *2 ECM Disconnect the mass air flow meter connector.
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Connect the intelligent tester to the DLC3.
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Turn the ignition switch to ON and 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 displayed on the tester.
Standard -40°C (-40°F) -
Reconnect the mass air flow meter connector.
OK
REPLACE MASS AIR FLOW METER Click here
NG
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CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
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Disconnect the mass air flow meter 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 B2-1 (THA) or B39-87 (THA) - Body ground Always 10 kΩ or higher -
Reconnect the mass air flow meter connector.
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Reconnect the ECM connector.
OK
REPLACE ECM Click here
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)
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