P0101

2AZ-FXE ENGINE CONTROL: SFI SYSTEM: P0101: Mass Air Flow Circuit Range / Performance Problem
P0101 - Mass Air Flow Circuit Range / Performance Problem

DESCRIPTION

The mass air flow meter sub-assembly is a sensor that measures the amount of air flowing through the throttle valve.

The hybrid vehicle control ECU uses this information to determine the fuel injection time and to provide the 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 flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant temperature value of the hot wire, current is applied to these components in the mass air flow meter sub-assembly. The voltage level is proportional to the airflow through the sensor, and the hybrid vehicle control ECU uses it to calculate the intake air volume.

The circuit is constructed so that the platinum hot wire and the temperature sensor create a bridge circuit, and the power transistor is controlled so that the potentials of A and B remain equal to maintain the predetermined temperature.

HINT
When any of these DTCs are set, check the air-flow rate by entering the following menus: Powertrain / Engine and ECT / Data List / MAF.





MONITOR DESCRIPTION

The mass air flow meter is a sensor that measures the amount of air flowing through the throttle valve. The hybrid vehicle control ECU uses this information to determine the fuel injection time and to provide an appropriate air fuel ratio. Inside the mass air flow 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 hybrid vehicle control ECU 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 hybrid vehicle control ECU varies the voltage applied to these components of the mass air flow meter. The voltage level is proportional to the airflow through the sensor, and the hybrid vehicle control ECU uses it to calculate the intake air volume.

The hybrid vehicle control ECU monitors the average engine load value ratio to check the mass air flow meter for malfunctions. The average engine load value ratio is obtained by comparing the average engine load calculated from the mass air flow 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 hybrid vehicle control ECU determines that the intake air volume is low, and if the average engine load value ratio is above the threshold value, the hybrid vehicle control ECU 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





- Connect the Techstream to the DLC3.

- Turn the power switch on (IG).

- Turn the Techstream on.

- Clear the DTCs DTC Check / Clear.

- Turn the power switch off and wait for at least 30 seconds.

- Turn the power switch on (IG) and turn the Techstream on.

- Put the engine in inspection mode Component Tests and General Diagnostics.

- Start the engine and warm it up until the engine coolant temperature reaches 70°C (158°F) or more [A].

- Drive the vehicle at approximately 50 mph (80 km/h) to 70 mph (112 km/h) for 5 minutes or more [B].

CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT
Drive while keeping the engine load as stable as possible.

- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

- Read the pending DTCs [C].

HINT
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

- Input the DTC: P0101.

- Check the DTC judgment result.





- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] and [C] again.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
Read freeze frame data using the Techstream. The hybrid vehicle control ECU records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0101)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read the DTCs.

Result:





HINT
If any DTCs other than P0101 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART SFI System
A -- Continue to next step.

2. CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leaks Testing and Inspection.

OK:

No leaks from the intake system.

NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.

3. CHECK PCV HOSE CONNECTIONS

(a) Check the PCV hose connections.

OK:

PCV hose is connected correctly and is not damaged.

NG -- REPAIR OR REPLACE PCV HOSE

OK -- REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Removal