P0111

DTC Code	DTC Name
P0111	Intake Air Temperature Sensor 1 Circuit Range / Performance

DESCRIPTION

The intake air temperature sensor, in the mass air flow meter, 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 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 intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R which is located inside the ECM.
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.

DTC No.	DTC Detection Condition	Trouble Area
P0111	When either of the following conditions is met (2 trip detection logic): The intake air temperature rise is small, from the previous trip warm-up to the following trip When the change in the intake air temperature after engine start is less than the threshold value	Mass air flow meter

DTC No.

DTC Detection Condition

Trouble Area

P0111

When either of the following conditions is met (2 trip detection logic):

The intake air temperature rise is small, from the previous trip warm-up to the following trip
When the change in the intake air temperature after engine start is less than the threshold value

Mass air flow meter

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 that the intake air temperature sensor value is stuck by monitoring the sensor after the power switch is turned off or after the engine is started.

MONITOR STRATEGY

Frequency of Operation

Once per driving cycle

CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.
Turn the power switch on (IG) and turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Click here.
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG) and turn the GTS on [A].
Put the engine in inspection mode (maintenance mode) Click here.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [B].
Idle the engine for 5 minutes or more [C].

Tech Tips

During steps [A] through [C], if the change in the intake air temperature is below 1°C (1.8°F), the intake air temperature sensor (mass air flow meter) is malfunctioning. It is not necessary to continue this procedure.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [D].
Read the pending DTC.
Tech Tips
- 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 and ECT / Utility / All Readiness.
Input the DTC: P0111.

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
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

Tech Tips

If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows NORMAL, the system is normal.
If the judgment result shows INCOMPLETE or N/A, perform steps [E] and [F].

Drive the vehicle at 40 km/h (25 mph) or more for a total of 5 minutes or more [E].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Check the DTC judgment result again [F].

Tech Tips

If the judgment result shows INCOMPLETE or N/A, perform steps [E] and [F] again.

WIRING DIAGRAM

Refer to DTC P0112 Click here.

INSPECTION PROCEDURE

Tech Tips

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.

PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0111)

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result

Result	Proceed to
DTC P0111 and other DTCs are output	A
DTC P0111 is output	B

Tech Tips

If any DTCs other than P0111 are output, troubleshoot those DTCs first.
Perform "Inspection After Repair" after replacing the mass air flow meter Click here.

B

REPLACE MASS AIR FLOW METER Click here

A

GO TO DTC CHART Click here

SFI SYSTEM, Diagnostic DTC:P0111