Troubleshooting

DTC P0110 INTAKE AIR TEMPERATURE CIRCUIT MALFUNCTION

CIRCUIT DESCRIPTION

DTC Detection Condition:

The intake air temperature sensor is built in the mass 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. 5 V power source voltage in the engine ECM is applied to the intake air temperature sensor from terminal THA (THAR) 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 (THAR) also changes. Based on this signal, the engine ECM increases the fuel injection volume to improve the driveability during cold engine operation.

Wiring Diagram:

Step 1 - 3:

Step 4 - 5:

INSPECTION PROCEDURE

CHECK FOR INTERMITTENT PROBLEMS

LEXUS hand-held tester only:
By putting the vehicle's ECM in the check mode, the 1 trip detection logic is possible instead of the 2 trip detection logic and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.
1. Clear the DTC.
2. Set the check mode.
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.