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DIAGNOSTIC ITEM
DTC
P0100
Mass Air Flow Sensor(AFS) Circuit Malfunction [Except Europe]
P0101
Mass Air Flow Sensor(AFS) Circuit Malfunction-Rationality
P0102
Mass Air Flow Sensor(AFS) Circuit Low Voltage
P0103
Mass Air Flow Sensor(AFS) Circuit High Voltage
DESCRIPTION
The Mass Air Flow sensor(AFS) is located near the air cleaner.
The sensor measures the mass of air passing through the air intake and generates a voltage signal. ECU
receives the voltage generated by the sensor and uses the signal to set fuel injector base pulse width and
ignition timing.
The resistance of the sensor decreases as mass air flow increases. Voltage and current flow is increased
to maintain the film's temperature and resistivity.
TROUBLESHOOTING GUIDE
Background
a. While the engine is running, the mass air flow sensor outputs a
voltage signal which corresponds to the mass of air flow.
b. ECU checks whether the voltage of this signal is at or above the
set value.
Check Area
a. At idle rpm
b. Or engine speed is 3000 r/min or more
Judgment Criteria
a. Sensor output voltage has continued to be 0.5V or lower for 4
sec.
Check Area
a. Throttle position sensor voltage is 12V or lower.
b. Engine speed is 2000 rpm or less.
Judgment Criteria
a. Sensor output voltage has continued to be 4.5V or higher for 4
seconds.
CIRCUIT DIAGRAM
DTC detection condition
Diagnostic item
a. Mass air flow sensor failed
b. Open or shorted mass air flow
sensor circuit, or loose
connector
c. ECU failed
Probable cause
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