DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
READ VALUE USING GTS (INTAKE AIR TEMPERATURE)
READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
REPLACE ECM
CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER.
REPAIR OR REPLACE HARNESS OR CONNECTOR
CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM.
REPLACE MASS AIR FLOW METER
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
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 detects the intake air temperature.
A thermistor built into the sensor changes its resistance value according to the intake air temperature.
The lower the intake air temperature, the higher the thermistor resistance value. The higher the intake air temperature, the lower the thermistor resistance value (See Fig. 1).
The intake air temperature sensor is connected to the ECM.
The 5 V power source voltage from the ECM is applied to the intake air temperature sensor from terminal THA 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 in accordance with the intake air temperature, the voltage at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability with a cold engine.

P0112DTC Detection Drive Pattern | DTC Detection Condition | Trouble Area |
Engine switch on (IG) for 0.5 seconds | Short in the intake air temperature sensor for 0.5 seconds (1 trip detection logic). | Short in intake air temperature sensor circuit
Intake air temperature sensor (built into mass air flow meter)
ECM
|
P0113DTC Detection Drive Pattern | DTC Detection Condition | Trouble Area |
Engine switch on (IG) for 0.5 seconds | Open in the intake air temperature sensor for 0.5 seconds (1 trip detection logic). | Open in intake air temperature sensor circuit
Intake air temperature sensor (built into mass air flow meter)
ECM
|
Related Data ListDTC No. | Data List |
P0112 P0113 | Intake Air |
If DTC P0112 and/or P0113 is stored, the following symptoms may appear:
Misfire
Combustion noise
Black smoke
White smoke
Lack of power
When DTC P0112 or P0113 is stored, check the intake air temperature by entering the following menus: Engine and ECT / Data List / Intake Air.
ReferenceTemperature Displayed | Malfunction |
-40°C (-40°F) | Open circuit |
140°C (284°F) or higher | Short circuit |
WIRING DIAGRAM

INSPECTION PROCEDURE
After replacing the ECM, the new ECM needs registration () and initialization ().
After replacing the fuel supply pump assembly, the ECM needs initialization ().
After replacing an injector assembly, the ECM needs registration ().
- Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.
1.READ VALUE USING GTS (INTAKE AIR TEMPERATURE) |
Connect the GTS to the DLC3.
Turn the engine switch on (IG) and turn the GTS on.
Enter the following menus: Engine and ECT / Data List / Intake Air.
Read the value.
- OK:
- Same as actual intake air temperature
ResultResult | Proceed to |
-40°C (-40°F) | A |
140°C (284°F) or higher | B |
OK (same as actual intake air temperature) | C |
If there is an open circuit, the GTS indicates -40°C (-40°F).
If there is a short circuit, the GTS indicates 140°C (284°F) or higher.
2.READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS) |
Disconnect the mass air flow meter connector.
Connect terminals 4 (THA) and 5 (E2) of the mass air flow meter wire harness side connector.
Connect the GTS to the DLC3.
Turn the engine switch on (IG) and turn the GTS on.
Enter the following menus: Engine and ECT / Data List / Intake Air.
Read the value.
- OK:
- 140°C (284°F) or higher
Text in Illustration*1 | Mass air flow meter |
*2 | ECM |
*a | Front view of wire harness connector (to Mass Air Flow Meter) |
3.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) |
Disconnect the mass air flow meter connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
for LHDTester Connection | Condition | Specified Condition |
C50-4 (THA) - C45-115 (THA) | Always | Below 1 Ω |
C50-5 (E2) - C45-92 (E2) | Always | Below 1 Ω |
- Standard Resistance:
for RHDTester Connection | Condition | Specified Condition |
C50-4 (THA) - C46-115 (THA) | Always | Below 1 Ω |
C50-5 (E2) - C46-92 (E2) | Always | Below 1 Ω |
4.READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS) |
Disconnect the mass air flow meter connector.
Connect the GTS to the DLC3.
Turn the engine switch on (IG) and turn the GTS on.
Enter the following menus: Engine and ECT / Data List / Intake Air.
Read the value.
Text in Illustration*1 | Mass Air Flow Meter |
*2 | ECM |
5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) |
Disconnect the mass air flow meter connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
for LHDTester Connection | Condition | Specified Condition |
C50-4 (THA) or C45-115 (THA) - Body ground | Always | 10 kΩ or higher |
- Standard Resistance:
for RHDTester Connection | Condition | Specified Condition |
C50-4 (THA) or C46-115 (THA) - Body ground | Always | 10 kΩ or higher |
7.CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER. |
Replace the mass air flow meter ().
8.REPAIR OR REPLACE HARNESS OR CONNECTOR |
Repair or replace the harness or connector.
9.CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM. |
10.REPLACE MASS AIR FLOW METER |
Replace the mass air flow meter ().
11.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
Connect the GTS to the DLC3.
Turn the engine switch on (IG) for 1 second.
Enter the following menus: Engine and ECT / Trouble Codes.
Confirm that the DTC is not output again.