Toyota RAV4 Service Manual: Intake air temperature sensor gradient too high
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
- Check any other dtcs output (in addition to dtc p0111)
- Connect the intelligent tester to the dlc3.
- Turn the ignition switch on.
- Turn the tester on.
- Enter the following menus: diagnosis / enhanced obd ii / dtc info / current codes.
- Read dtcs.
Hint:
If any dtcs other than p0111 are output, troubleshoot those dtcs first.
Intake air temperature circuit malfunction
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 ac ...
Engine coolant temperature circuit
Description
A thermistor, whose resistance value varies according to the ect, is built
into the engine coolant
temperature (ect) sensor.
The structure of the sensor and its connection to th ...
Other materials:
Diagnosis system
Description
Power door lock control system data can be read in the
data link connector 3 (dlc3) of the vehicle. When the
system seems to be malfunctioning, use the intelligent
tester to check for malfunctions and perform repairs.
Check dlc3
The ecu uses iso 15765-4 for communi ...
Replacement
Replace generator drive end frame bearing
Remove the 4 screws and bearing retainer.
Using sst and a hammer, tap out the bearing.
Sst 09950-60010 (09951-00250), 09950-70010
(09951-07100)
Using sst and a press, press in a new bearing.
Sst 09950-60010 (09951-00250), 09 ...
Precaution
Handling precaution
When handling the electronic parts:
Avoid any impact to electronic parts such as
ecus and relays. Replace with new ones if
dropped or subjected to a severe blow.
Do not expose any electronic parts to high
temperatures and humidity.
Do not touch the connec ...