Lexus IS250 IS220d GSE20 ALE20 2AD-FHV ENGINE CONTROL SYSTEM
READ VALUE OF INTAKE AIR TEMPERATURE SENSOR
CHECK MASS AIR FLOW METER (OPEN IN INTAKE AIR TEMPERATURE SENSOR)
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
CHECK MASS AIR FLOW METER (SHORT IN INTAKE AIR TEMPERATURE SENSOR)
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
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 sensor is built into the mass air flow meter and senses the intake air temperature.
A thermistor built in the sensor changes its resistance value according to the intake air temperature.
The lower the intake air temperature, the greater the thermistor resistance value. The higher the intake air temperature, the lower the thermistor resistance value (see figure 1).
The intake air temperature sensor is connected to the ECM.
The 5 V power source voltage in the ECM is applied to the intake air temperature sensor from terminal THA (THAR) via resistor R.
The resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes in accordance with changes in the intake air temperature, the potential at terminal THA (THAR) also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability with a cold engine.
| DTC No. | DTC Detection Condition | Trouble Area |
| P0110 | Open or short in IAT sensor circuit for 0.5 seconds (1 trip detection logic) |
Open or short in IAT sensor circuit IAT sensor ECM |
| P0112 | Short in IAT sensor circuit for 0.5 seconds (1 trip detection logic) |
Open or short in IAT sensor circuit IAT sensor ECM |
| P0113 | Open in IAT sensor circuit for 0.5 seconds (1 trip detection logic) |
Open or short in IAT sensor circuit IAT sensor ECM |
- HINT:
- When DTC P0110, P0112, or P0113 is detected, check the intake air temperature by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / Intake Air.
| Temperature Displayed | Malfunction |
| -40°C (-40°F) | Open circuit |
| 140°C (284°F) or more | Short circuit |
WIRING DIAGRAM
INSPECTION PROCEDURE
- NOTICE:
- After replacing the ECM, the new ECM needs registration and initialization .
- HINT:
- If DTCs relating to different systems are output, and they share terminal E2 as their ground, check this ground circuit first.
| 1.READ VALUE OF INTAKE AIR TEMPERATURE SENSOR |
Connect the intelligent tester to the DLC3.
Turn the engine switch ON (IG) and turn the intelligent tester ON.
Enter the following menus: Powertrain / Engine / Data List / Intake Air.
Read the value.
- OK:
- Same value as the actual air temperature.
- Result:
Temperature Displayed Proceed to -40°C (-40°F) A 140°C (284°F) or more B OK (same as air temperature near intake manifold) C
- HINT:
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| A | |
| 2.CHECK MASS AIR FLOW METER (OPEN IN INTAKE AIR TEMPERATURE SENSOR) |
Disconnect the E83 Mass Air Flow (MAF) meter connector.
Connect terminals THA and E2 of the MAF meter wire harness side connector.
Connect the intelligent tester to the DLC3.
Turn the engine switch ON (IG) and turn the tester ON.
Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.
Read the value displayed on the tester.
- Standard:
- 140°C (284°F) or more
Reconnect the MAF meter connector.
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| NG | |
| 3.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) |
Disconnect the E83 MAF meter connector.
Disconnect the E59 ECM connector.
Measure the resistance.
- Standard resistance:
Tester Connections Specified Conditions THA (E83-4) - THA (E59-110) Below 1 Ω E2 (E83-5) - ETHA (E59-87)
Reconnect the MAF meter connector.
Reconnect the ECM connector.
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| OK | ||
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| 4.CHECK MASS AIR FLOW METER (SHORT IN INTAKE AIR TEMPERATURE SENSOR) |
Disconnect the E83 MAF meter connector.
Connect the intelligent tester to the DLC3.
Turn the engine switch ON (IG) and turn the intelligent tester ON.
Enter the following menus: Powertrain / Engine / Data List / Intake Air.
Read the value.
- OK:
- -40°C (-40°F)
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| NG | |
| 5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) |
Disconnect the E83 MAF meter connector.
Disconnect the E59 ECM connector.
Measure the resistance.
- Standard resistance:
Tester Connections Specified Conditions THA (E83-4) or THA (E59-110) - Body ground 10 kΩ or higher
Reconnect the MAF meter connector.
Reconnect the ECM connector.
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| OK | ||
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