Engine General Information and Diagnosis: 1A-63
DTC P0103: Mass or Volume Air Flow Circuit High Input
S7RS0B1104019
Wiring Diagram
Refer to “DTC P0101: Mass or Volume Air Flow Circuit Range / Performance”.
DTC Detecting Condition and Trouble Area
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.
DTC Troubleshooting
NOTE
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors referring to “Inspection of ECM and Its Circuits”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and
confirm that the trouble has been corrected.
DTC detecting condition Trouble area
MAF sensor output voltage is higher than 4.85 V for 0.5 seconds
continuously.
(1 driving cycle detection logic)
• Open or short in MAF sensor circuit
• MAF sensor
•ECM
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”.
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” for normal value.)
Is normal value indicated?
Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
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 “BLK/RED” wire terminal of MAF and
IAT sensor connector.
Is voltage 10 – 14 V?
Go to Step 4. “BLK/RED” wire is open
circuit.
4 MAF sensor ground circuit check
1) Turn OFF ignition switch, measure resistance between
“GRY” 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) Remove ECM from its bracket with ECM connectors
connected.
2) Measure resistance between “C37-27” terminal of ECM
connector and engine ground.
Is resistance below 5
Ω
?
“GRY” wire is open or
high resistance circuit.
ECM grounds “E23-31”,
“C37-58”, “C37-15” and/
or “C37-30” circuit are
open or high resistance.
If wires are OK,
substitute a known-
good ECM and recheck.
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