P0112

DTC P0110 INTAKE AIR TEMPERATURE CIRCUIT
DTC P0112 INTAKE AIR TEMPERATURE CIRCUIT LOW INPUT
DTC P0113 INTAKE AIR TEMPERATURE CIRCUIT HIGH INPUT

CIRCUIT DESCRIPTION

DTC Detection Condition:

The Intake Air Temperature (IAT) sensor, built in the Mass Air Flow (MAF) meter, monitors the intake air temperature. The IAT sensor has a thermistor that varies its resistance depending on the intake air temperature. When the intake air temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. The variations in resistance are reflected as voltage changes to the ECM terminal (see Fig. 1).

The IAT sensor is connected to the ECM. The 5 V power source voltage in the ECM is applied to the IAT sensor from terminal THA via resistor R.

The resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor changes in accordance with changes in the intake air temperature, the voltage at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve the driveability during cold engine operation.

HINT: After confirming DTC "P0110, P0112 or P0113", use the hand-held tester to confirm the intake air temperature in the "DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL".

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Component Operating Range:

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 fault in the IAT sensor and sets a DTC.

Example: When the sensor voltage output is -40 Degrees C (-40 Degrees F) or more than 140 Degrees C (284 Degrees F) and if either condition continues 0.5 seconds or more, the ECM will set a DTC. This monitor runs 0.5 seconds after the ignition switch is turned ON.

Wiring Diagram:

Step 1:

Step 2-3:

Step 4-5:

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.