8ZR-FXE ENGINE CONTROL  SFI SYSTEM  P010012  Mass or Volume Air Flow Sensor "A" Circuit Short to Battery  P010014  Mass or Volume Air Flow Sensor "A" Circuit Short to Ground or Open  

The mass air flow meter sub-assembly is a sensor that measures the intake air volume using the following built-in components:

Intake air flows over the temperature sensor (before heater), the heater, and then the temperature sensor (after heater) on the silicon chip sensor in the by-pass passage. As the intake air is warmed up when it is exposed to the heater, the temperature of the intake air flowing over the temperature sensor (after heater) is higher than that over the temperature sensor (before heater). The difference in temperature of the intake air at each temperature sensor varies depending on the velocity of the intake air that flows over the silicon chip sensor. The temperature sensor bridge circuit detects the difference in temperature and the control circuit converts it into a pulse signal and outputs it to the ECM. When the temperature detected by the temperature sensor (before heater) is higher than that detected by the temperature sensor (after heater), backflow of the intake air is detected.

The ECM calculates the intake air amount based on the pulse signal received from the mass air flow meter sub-assembly, and uses it to determine the fuel injection duration necessary for an optimal air-fuel ratio.

The heater control bridge circuit includes temperature sensors and power transistor, and maintains the heater temperature at a specific temperature.

HINT:

When DTCs are stored, the ECM enters fail-safe mode. During fail-safe mode, the ECM calculates the fuel injection duration based on the engine speed and throttle valve angle. Fail-safe mode continues until a pass condition is detected.

5.073,1.719 4.917,0.917 4.917,0.917 4.75,0.917 true 5.073,2.521 5,3 5,3 4.833,3 true 0.667,3 0.833,3.5 0.833,3.5 1,3.5 true 6.5,2.333 6.333,2.333 6.333,2.333 6.26,2.063 true 0.417,0.333 0.667,0.5 0.25,0.167 10 false *1 6.427,1.49 6.677,1.646 0.25,0.156 10 false *a 3.125,1.49 3.375,1.656 0.25,0.167 10 false *b 4.635,2.917 4.885,3.073 0.25,0.156 10 false *c 4.531,0.844 4.781,1.01 0.25,0.167 10 false *d 3.646,1.854 3.958,2.01 0.313,0.156 10 false *e 1.063,3.427 1.375,3.583 0.313,0.156 10 false *f 6.583,2.25 6.833,2.406 0.25,0.156 10 false *f

*1	Mass Air Flow Meter Sub-assembly	-	-
*a	Upstream Side	*b	Downstream Side
*c	Heater	*d	Temperature Distribution WithoutAirflow
*e	Flow Rate Detection by TemperatureDifferential	*f	Intake Air

If there is a defect or an open or short circuit in the mass air flow meter sub-assembly, the frequency level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the mass air flow meter sub-assembly circuit and stores a DTC.

Example:

When the sensor output frequency remains less than 0.1 kHz, or higher than 9.8 kHz for 3 seconds, the ECM stores a DTC.

HINT:

·

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

Click hereEngine / Hybrid System>8ZR-FXE (ENGINE CONTROL)>SFI SYSTEM>DTC CHECK / CLEAR202304,999999,_51,_080778,_0393982,RM100000002BDLJ,

·

When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

Click hereEngine / Hybrid System>8ZR-FXE (ENGINE CONTROL)>SFI SYSTEM>DTC CHECK / CLEAR202304,999999,_51,_080778,_0393982,RM100000002BDLJ,

NOTICE:

·

Vehicle Control History may be stored in the hybrid vehicle control ECU if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the freeze frame data and Vehicle Control History can be useful for troubleshooting.

Click hereEngine / Hybrid System>HYBRID / BATTERY CONTROL>PA10 HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY)>VEHICLE CONTROL HISTORY (RoB)202304,999999,_51,_080773,_0600291,RM100000002BBVZ,

(Select Powertrain in Health Check and then check the time stamp data.)

·

If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.

Click hereEngine / Hybrid System>HYBRID / BATTERY CONTROL>PA10 HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY)>VEHICLE CONTROL HISTORY (RoB)202304,999999,_51,_080773,_0600291,RM100000002BBVZ,

HINT:

Read Freeze Frame Data using the GTS. The ECM 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.