Toyota Sienna Service Manual: Intake Air Temperature Sensor Gradient Too High
DTC P0111 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 becomes low, the resistance of the thermistor increases. When the temperature becomes 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.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|
P0111 |
|
Mass air flow meter assembly |
MONITOR DESCRIPTION
The ECM performs OBD II monitoring based on the values from the intake air temperature sensor. If there is no change in the sensor value, 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 ignition is started (short soak or long soak).
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All:
After engine stop:
After cold engine start:
TYPICAL MALFUNCTION THRESHOLDS
After engine stop:
After cold engine start:
WIRING DIAGRAM
Refer to DTC P0110.
INSPECTION PROCEDURE
1 CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0111)
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to the ON position.
- Turn the tester on.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read the DTCs.
Result
HINT: If any DTCs other than P0111 are output, troubleshoot those DTCs first.
GO TO DTC CHART
Intake Air Temperature Circuit/ Intake Air Temperature Circuit Low Input/
Intake Air Temperature Circuit High Input
DTC P0110 Intake Air Temperature Circuit
DTC P0112 Intake Air Temperature Circuit Low Input
DTC P0113 Intake Air Temperature Circuit High Input
DESCRIPTION
The Intake Air Temperature (IAT) sensor, ...
Engine Coolant Temperature Circuit
DTC P0115 Engine Coolant Temperature Circuit
DTC P0117 Engine Coolant Temperature Circuit Low Input
DTC P0118 Engine Coolant Temperature Circuit High Input
DESCRIPTION
A thermistor is built into t ...
Other materials:
Installation
HINT:
Install the RH side by the same procedure as the LH side.
1. INSTALL FRONT DISC BRAKE CYLINDER SLIDE BUSH
(a) Apply the lithium soap base glycol grease to a new
front disc brake cylinder slide bush.
(b) Install the cylinder slide bush to the bottom side of
the front disc brake cyli ...
If the shift lever cannot
be shifted from P
If the shift lever cannot be shifted with your foot on the brake
pedal, there may be a problem with the shift lock system (a system
to prevent accidental operation of the shift lever). Have the
vehicle inspected by your Toyota dealer immediately.
The following steps may be used as an emergency ...
Automatic transaxle fluid
On-vehicle inspection
1. CHECK FLUID LEVEL
HINT:
Drive the vehicle so that the engine and transaxle are at
normal operating temperature.
Fluid temperature:
70 to 80°C (158 to 176°F)
(a) Park the vehicle on a level surface and set the
parking brake.
(b) With the engine idling and the ...
