vehicle).
- During the test, do not use an exhaust air duct on the tail exhaust pipe assembly.
MONITOR DESCRIPTION
The mass air flow meter sub-assembly is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses this information
to determine the fuel injection time and to provide an appropriate air fuel ratio. Inside the mass air flow meter sub-assembly, there is a heated
platinum wire which is exposed to the flow of intake air. By applying a specific electrical current to the wire, the ECM heats it to a specific
temperature. The flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant current value,
the ECM varies the voltage applied to these components of the mass air flow meter sub-assembly. The voltage level is proportional to the airflow
through the sensor, and the ECM uses it to calculate the intake air volume.
The ECM monitors the average engine load value ratio to check the mass air flow meter sub-assembly for malfunctions. The average engine load
value ratio is obtained by comparing the average engine load calculated from the mass air flow meter sub-assembly output to the average engine load
estimated from the driving conditions, such as the engine speed and the throttle opening angle. If the average engine load value ratio is below the
threshold value, the ECM determines that the intake air volume is low, and if the average engine load value ratio is above the threshold value, the
ECM determines that the intake air volume is high.
If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is set.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
CONFIRMATION DRIVING PATTERN
No comments:
Post a Comment