Intake Air Temperature Sensor Gradient Too High (P0111)

DESCRIPTION

• The intake air temperature sensor, mounted on 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 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.

DTC No.	DTC Detection Condition	Trouble Area
P0111	Either of the following condition is met (2 trip detection logic). The intake air temperature change from the previous trip warm up to the following trip is small. 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 when the intake air temperature sensor value is stuck by performing monitoring after the ignition switch is turned off or the engine is started (short soak or long soak).

MONITOR STRATEGY

Related DTCs	P0111: Intake Air Temperature Sensor Rationality (After Engine Stop) P0111: Intake Air Temperature Sensor Rationality (After Cold Engine Start)
Required Sensors/Components (Main)	Intake air temperature sensor
Required Sensors/Components (Related)	-
Frequency of Operation	Once per driving cycle
Duration	-
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS All

Monitor runs whenever the following DTCs are not stored

None

After Engine Stop

All of the following conditions are met	-
Time after engine start	10 seconds or more
Battery voltage	10.5 V or higher
Mass air flow meter circuit fail (P0102, P0103)	Not detected
Intake air temperature sensor circuit fail (P0112, P0113)	Not detected
Engine coolant temperature sensor circuit fail (P0115, P0117, P0118)	Not detected
Soak timer fail (P2610)	Not detected
Engine coolant temperature at ECM started by internal engine off timer	-40°C (-40°F) or higher
Engine coolant temperature before engine stop	70 °C or higher
Time that mass air flow is low before engine stop	2100 seconds
Accumulated mass air flow amount before engine stop	2580 g or more
Soak time	30 minutes

After Cold Engine Start

All of the following conditions are met	-
Soak time	5 hours or more
Time after engine start	10 seconds or more
Mass air flow meter circuit fail (P0102, P0103)	Not detected
Intake air temperature sensor circuit fail (P0112, P0113)	Not detected
Engine coolant temperature sensor circuit fail (P0115, P0117, P0118)	Not detected
Soak timer fail (P2610)	Not detected
Engine coolant temperature	70 °C or higher
Accumulated mass air flow amount	2580 g or more
Either of the following conditions 1 or 2 is met:	-
1. Duration while engine load is low	120 seconds or more
2. Duration while engine load is high	10 seconds or more

TYPICAL MALFUNCTION THRESHOLDS After Engine Stop

Intake air temperature change

Less than 1 °C

After Cold Engine Start

Intake air temperature change

Less than 1 °C

CONFIRMATION DRIVING PATTERN

1. 1
   Connect the Techstream to the DLC3.
2. 2
   Turn the ignition switch to ON and turn the Techstream on.
3. 3
   Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) (See page ).
4. 4
   Turn the ignition switch off and wait for at least 30 seconds.
5. 5
   Turn the ignition switch to ON and turn the Techstream on [A].
6. 6
   Start the engine and warm it up until the engine coolant temperature reaches 75 °C or higher [B].
7. 7
   Idle the engine for 5 minutes or more [C].

   HINT:

   During steps [A] through [C], if the change in the intake air temperature is below 1 °C, the intake air temperature sensor (mass air flow meter) is malfunctioning. It is not necessary to continue this procedure.

8. 8
   Enter the following menus: Powertrain / Engine / Trouble Codes [D].
9. 9
   Read the Pending DTCs.

   HINT:

   • If a pending DTC is output, the system is malfunctioning.
   • If a pending DTC is not output, perform the following procedure.
10. 10
    Enter the following menus: Powertrain / Engine / Utility / All Readiness.
11. 11
    Input the DTC: P0111.
12. 12
    Check the DTC judgment result.

    Techstream 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

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE or N/A, perform steps [E] and [F].
13. 13
    Drive the vehicle at 40 km/h 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.

14. 14
    Check the DTC judgment result again [F].

    HINT:

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

15. 15
    If no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).
    

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0112 (See page ).

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. 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

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

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

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

HINT:

• If any DTCs other than P0111 are output, troubleshoot those DTCs first.
• Perform "Inspection After Repair" after replacing the mass air flow meter (See page ).

A

GO TO DTC CHART

B

REPLACE MASS AIR FLOW METER