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.
|
DTC No. | DTC Detection Condition |
Trouble Area | | P0111 |
When either condition below 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 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 |
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 (IAT) sensor | |
Required Sensors/Components (Related) |
- | | Frequency of Operation |
Once per driving cycle | | Duration |
10 seconds or more | | MIL Operation |
2 driving cycles | | Sequence of Operation |
None | TYPICAL ENABLING CONDITIONS All |
Monitor runs whenever following DTCs are not present |
P0102, P0103 (Mass air flow meter) P0112, P0113 (Intake air temperature sensor)
P0115, P0117, P0118 (Engine coolant temperature sensor) P2610 (Soak timer) | After Engine Stop |
Time after engine start | 10 seconds or more | |
Battery voltage | 10.5 V or more | |
ECT change since engine stop | -40°C (-40°F) or more | |
ECT before engine stop | 70°C (158°F) or more | |
Accumulated MAF amount before engine stop | 6754 g or more | |
Key-off duration | 30 minutes | After Cold Engine Start |
Key-off duration | 5 hours | |
Time after engine start | 10 seconds or more | |
ECT | 70°C (158°F) or more | |
Accumulated MAF amount | 6754 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 |
IAT change | Less than 1°C (2°F) | After Cold Engine Start |
IAT change | Less than 1°C (2°F) | CONFIRMATION DRIVING PATTERN
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON and turn the Techstream on.
- Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
- Turn the ignition switch off and wait for at least 30 seconds.
- Turn the ignition switch to ON and turn the Techstream on [A].
- Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher [B].
- 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 (33.8°F), the intake air temperature sensor (MAF 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 DTCs.
HINT:
- 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.
|
Tester 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 ABNORMAL, the system has a malfunction.
- 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].
HINT:
If the judgment result shows INCOMPLETE or N/A, perform steps [E] and [F] again.
- 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
). 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 and ECT / Trouble Codes.
(e) Read DTCs. Result |
Result | Proceed to | |
P0111 and other DTCs are output | A | |
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 | |
