1A
DTC P0103: Mass Air Flow Circuit High Input
Wiring Diagram
1. MAF and IAT sensor 3. Main relay 5. To other sensors
2. Ignition switch 4. ECM    
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 MAF sensor output is more than the specified value for the specified time continuously.
(1 driving cycle detection logic)
• Open or short in MAF sensor circuit
• MAF 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
MAF sensor and its circuit check
1) Connect scan tool to DLC with ignition switch turned OFF.
2) Start engine and check MAF value displayed on scan tool. (Refer to Scan Tool Data:M13A with VVT for normal value.)
Is normal value indicated?
Intermittent trouble. Check for intermittent referring to Intermittent and Poor Connection Inspection .
Go to Step 3.
3
MAF sensor power supply voltage check
1) Disconnect connector from MAF and IAT sensor with ignition switch tuned OFF.
2) Turn ON ignition switch, measure voltage between engine ground and “BLU/BLK” wire terminal of MAF and IAT sensor connector.
Is voltage 10 – 14 V?
Go to Step 4.
“BLU/BLK” wire in open circuit.
4
MAF sensor ground circuit check
1) Turn OFF ignition switch, measure resistance between “YEL/BLK” wire terminal of MAF and IAT sensor connector and engine ground.
Is resistance below 5 Ω?
Go to Step 6.
Go to Step 5.
5
Ground circuit check
1) Measure resistance between “E119-32” terminal of ECM connector and vehicle body ground.
Is resistance below 5 Ω?
“YEL/BLK” wire in open or high resistance circuit.
ECM grounds “E119-1”, “E117-2” and/or “E117-1” circuit in open or high resistance.
If wires are OK, substitute a known-good ECM and recheck.
6
MAF sensor signal circuit check
1) Disconnect connectors from ECM with ignition switch turned OFF.
2) Measure voltage between “YEL/GRN” wire terminal of MAF and IAT sensor connector and engine ground.
Is voltage 0 V?
Go to Step 7.
“YEL/GRN” wire shorted to other circuits.
7
MAF sensor output signal check
1) Connect connector to MAF and IAT sensor and ECM with ignition switch turned OFF.
2) Measure voltage between “E119-14” and “E119-32” terminal of ECM connector referring to Mass Air Flow (MAF) and Intake Air Temperature (IAT) Sensor On-Vehicle Inspection (With VVT):M13A .
Is each value within specified?
Substitute a known-good ECM and recheck.
Faulty MAF and IAT sensor.
NOTE:
Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.