Description
Refer to dtc p0100 (see page es-86).
Monitor description
The maf meter 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 maf meter, 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 maf meter. 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 maf meter for malfunctions. The average engine load value ratio is obtained by comparing the average engine load calculated from the maf meter 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
Wiring diagram
Refer to dtc p0100 (see page es-88).
Confirmation driving pattern
Hint:
Performing this confirmation pattern will activate the mass air flow performance monitor.
Inspection procedure
Hint:
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
Hint:
If any dtcs other than p0101 are output, troubleshoot those dtcs first.
Ok:
No leakage from air induction system.
Ok:
Pcv hose is connected correctly and is not damaged.
Replace mass air flow meter
Inspection
Inspect cylinder head for warpage
Using a precision straightedge and feeler gauge,
measure the warpage of the contact surfaces of the
cylinder block and manifolds.
Maximum warpage:
0.08 Mm (0.0032 In.)
If the warpage is greater than the maximum, replace
the cylinder head sub-a ...
If the shift lever cannot
be shifted from p
If the shift lever cannot be shifted with your foot on the brake
pedal, there may be a problem with the shift lock system (a system
to prevent accidental operation of the shift lever). Have the
vehicle inspected by your toyota dealer immediately.
The following steps may be used as an emergency ...
Skid control sensor (for 2wd)
Components
Removal
Hint:
Use the same procedures for the lh side and rh side.
The procedures listed below are for the lh side.
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery termin ...