Troubleshooting

DTC P0110 INTAKE AIR TEMPERATURE CIRCUIT MALFUNCTION

CIRCUIT DESCRIPTION




The intake air temperature sensor is built into the air flow meter and senses the intake air temperature.

A thermistor built in the sensor changes the resistance value according to the intake air temperature.

The lower the intake air temperature, the greater the thermistor resistance value, and the higher the intake air temperature, the lower the thermistor resistance value (See fig. 1).

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

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

DTC Detecting Condition:

If the ECM detects the DTC P0110, it operates the fail-safe function in which the intake air temperature is assumed to be 20 °C (68 °F).

Wiring Diagram:

Step 1 - 2:

Step 3 - 5:

INSPECTION PROCEDURE

HINT:
- If DTC P0110 (Intake Air Temperature Circuit Malfunction), P0115 (Water Temperature Circuit Malfunction), P0120 (Throttle/Pedal Position Sensor/Switch "A" Malfunction) are output simultaneously, E2 (Sensor Ground) may be open.
- Read freeze frame data using hand-held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air-fuel ratio lean or rich, etc. at the time of the malfunction.