The intake air temperature sensor, mounted on the mass air flow meter sub-assembly, monitors the intake air temperature. The intake air temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the intake air temperature 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 intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
Resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes, according to changes in the intake air temperature, 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.
When DTC P011011 is stored, the ECM enters fail-safe mode. During fail-safe mode, the intake air temperature is estimated to be 20°C (68°F) by the ECM. Fail-safe mode continues until a pass condition is detected, and the ignition switch is then turned off.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| P011011 | Intake Air Temperature Sensor 1 Bank 1 Circuit Short to Ground | The intake air temperature sensor output voltage is less than 0.176 V for 0.5 seconds or more (1 trip detection logic). | ·
Short in intake air temperature sensor circuit ·
Intake air temperature sensor (mass air flow meter sub-assembly) ·
ECM |
Comes on | DTC stored | SAE: P0112 |
When a DTC is output, check the Data List item "Intake Air Temperature" using the GTS.
| DTC No. | Intake Air Temperature | Malfunction |
|---|---|---|
| P011011 | Higher than 128°C (262°F) | Short to ground in THA circuit |
If the Data List displays a normal value, the normal value may be due to a temporary recovery from the malfunction condition. Check for intermittent problems.
The ECM monitors the sensor voltage and uses this value to calculate the intake air temperature. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a malfunction in the intake air temperature sensor (mass air flow meter sub-assembly) circuit, illuminates the MIL and stores a DTC.
Example:
If the intake air temperature sensor output voltage is less than 0.176 V for 0.5 seconds or more, the ECM will illuminate the MIL and store this DTC.
| Frequency of Operation | Continuous |
After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON [A].
Turn the GTS on.
Wait 0.5 seconds or more [B].
Enter the following menus: Powertrain / Engine / Trouble Codes [C].
Read the pending DTCs.
If a pending DTC is output, the system is malfunctioning.
If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P011011.
Check the DTC judgment result.
| GTS Display | Description |
|---|---|
| NORMAL | ·
DTC judgment completed ·
System normal |
| ABNORMAL | ·
DTC judgment completed ·
System abnormal |
| INCOMPLETE | ·
DTC judgment not completed ·
Perform driving pattern after confirming DTC enabling conditions |
If the judgment result is NORMAL, the system is normal.
If the judgment result is ABNORMAL, the system is malfunctioning.
[A] to [C]: Normal judgment procedure.
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
When clearing the permanent DTCs, do not disconnect the cable from the battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.
Refer to DTC P010012.
Read Freeze Frame Data using the GTS. The ECM records vehicle and driving condition information as Freeze Frame Data the moment a DTC is stored. When troubleshooting, Freeze Frame Data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
| *1 | Mass Air Flow Meter Sub-assembly |
| *2 | ECM |
Disconnect the mass air flow meter sub-assembly connector.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Data List / Intake Air Temperature.
| Tester Display |
|---|
| Intake Air Temperature |
According to the display on the GTS, read the Data List.
| GTS Display | Specified Condition |
|---|---|
| Intake Air Temperature | -40°C (-40°F) |
Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.
| Proceed to |
|---|
| OK |
| NG |
OK
NG
Disconnect the mass air flow meter sub-assembly connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| C17-4 (THA) or C71-165 (THA) - Body ground and other terminals | Always | 10 kΩ or higher |
| Proceed to |
|---|
| OK |
| NG |
OK
NG