Description
The intake air temperature (iat) sensor, mounted on the mass air flow (maf) meter, 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 is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the ecm as voltage changes (see fig. 1).
The iat sensor is powered by a 5 v supply from the tha terminal of the ecm, via resistor r.
Resistor r and the iat sensor are connected in series. When the resistance value of the iat sensor changes, according to changes in the iat, the voltage at terminal tha also varies. Based on this signal, the ecm increases the fuel injection volume when the engine is cold to improve driveability.
Monitor description
The ecm performs obd ii monitoring based on the values from the intake air temperature sensor. If there is no change of the sensor value within the normal range, the ecm will not be able to perform obd ii monitoring or will misdiagnose that there is a malfunction in the sensor. The ecm detects the stuck intake air temperature sensor value by performing monitoring after the ignition switch is turned off or the engine is started (short soak or long soak).
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Wiring diagram
Refer to dtc p0110 (see page es-88).
Inspection procedure
Hint:
If any dtcs other than p0111 are output, troubleshoot those dtcs first.
System voltage
Description
The battery supplies electricity to the ecm even when the ignition switch is
in the off position. This
power allows the ecm to store data such as dtc history, freeze frame data and
fuel trim values. If the
battery voltage falls below a minimum level, the memory is cleared and ...
Tire pressure warning light circuit
Description
If the tire pressure warning ecu detects trouble, the tire pressure warning
light turns on and tire pressure
monitor is canceled at the same time. At this time, the ecu records a dtc in
memory.
Connect terminals tc and cg of the dlc3 to make the tire pressure warning light
bli ...
On-vehicle inspection
Check battery condition
Notice:
If the battery is weak or if the engine is difficult to
start, perform the following procedures.
Check the battery for damage and deformation. If
severe damage, deformation or leakage is found,
replace the battery.
Check the electrolyte quantity of e ...