1A
DTC P0112: Intake Air Temperature Sensor Circuit Low
Wiring Diagram
1. MAF and IAT sensor 2. ECM 3. To other sensors 4. From main relay
DTC Detecting Condition and Trouble Area
DTC detecting condition Trouble area
DTC will be set when all of the following conditions are detected for 0.5 seconds continuously.
• Engine is running
• Voltage of IAT sensor output is less than the specified value (High intake air temperature (low voltage/low resistance))
(1 driving cycle detection logic)
• IAT sensor circuit
• IAT sensor
• ECM
DTC Confirmation Procedure
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and run it for 10 sec.
4) Check DTC and pending DTC.
DTC Troubleshooting
Step Action YES NO
1
Was “Engine and Emission Control System Check” performed?
Go to Step 2.
Go to Engine and Emission Control System Check:M13A with VVT .
2
IAT sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch.
3) Check intake air temp. displayed on scan tool.
Is 119 °C (246 °F) indicated?
Go to Step 3.
Intermittent trouble. Check for intermittent referring to Intermittent and Poor Connection Inspection .
3
ECM voltage check
1) Disconnect connector from MAF and IAT sensor with ignition switch turned OFF.
2) Check for proper connection to MAF and IAT sensor at “LT GRN/BLK” and “BLK/BLU” wire terminals.
3) If OK, then turn ON ignition switch, measure voltage between “LT GRN/BLK” wire terminal of IAT sensor connector (1) and vehicle body ground.
Is voltage about 4 – 6 V?
Go to Step 6.
Go to Step 4.
4
IAT circuit insulation check
1) Disconnect connectors from ECM with ignition switch turned OFF.
2) Measure resistance between “LT GRN/BLK” wire terminal of MAF and IAT sensor connector and vehicle body ground.
Is resistance infinity?
Go to Step 5.
“LT GRN/BLK” wire shorted to ground circuit.
If wire are OK, substitute a known-good ECM and recheck.
5
IAT short circuit check
1) Turn ON ignition switch.
2) Measure voltage between “LT GRN/BLK” wire terminal of MAF and IAT sensor connector and vehicle body ground.
Is voltage about 0 V?
Go to Step 6.
“LT GRN/BLK” wire shorted to other circuits.
If wire are OK, substitute a known-good ECM and recheck.
6
IAT sensor for performance check
1) Check IAT sensor according to Mass Air Flow (MAF) and Intake Air Temperature (IAT) Sensor On-Vehicle Inspection (With VVT):M13A .
Is it in good condition?
Substitute a known-good ECM and recheck.
Replace MAF and IAT sensor.
NOTE:
Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.