OPERATION
- Power is supplied by the engine control relay (terminal No. 1) to the air flow sensor (terminal No. 2), and the air flow sensor (terminal No. 4) is grounded through the engine-A/T-ECU (terminal No. 88) <Vehicle except for Australia, South africa and Hong kong> or (terminal No. 96) <Vehicle for Australia, South africa and Hong kong>.
- The air flow sensor (terminal No. 3) outputs a sensor signal, which is input into the engine-A/T-ECU (terminal No. 63).
FUNCTION
- The air flow sensor outputs amperage that varies in accordance with the intake air volume.
- The engine-A/T-ECU uses the amperage output by the air flow sensor and the engine speed signal in order to determine the basic injection duration of the injector.
TROUBLE JUDGMENT
Check Condition
- After 3 seconds have passed since the ignition switch was turned to "ON" position.
Judgment Criteria
- Air flow sensor output voltage has continued to be 0.2 V or lower for 2 seconds.
- Air flow sensor output voltage has continued to be 4.9 V or higher for 2 seconds.
PROBABLE CAUSE
- Failed air flow sensor
- Open/short circuit in air flow sensor circuit or loose connector contact
- Failed engine-A/T-ECU
)
Q: Is the check result normal?
YES:
Go to Step 3 
.NO: Repair.
- Disconnect connector, and measure at harness side.
- Ignition switch: ON
- Voltage between terminal No. 2 and earth.
OK: System voltage
Q: Is the check result normal?
YES:
Go to Step 5 .NO: Go to Step 4
.)
Q: Is the check result normal?
YES:
- Check intermediate connector C-17, and repair if necessary. If intermediate connector is normal, check and repair harness between B-08 (terminal No. 2) air flow sensor connector and B-17X (terminal No. 1) engine control relay connector.
- Check power supply line for open/short circuit.
- Disconnect connector, and measure at harness side.
- Resistance between terminal No. 4 and earth.
OK: 2 Ω
or less
Q: Is the check result normal?
YES:
Go to Step 9 .NO: Go to Step 6
.)
Q: Is the check result normal?
YES:
Go to Step 7 .NO: Repair.
NOTE: Before checking harness, check intermediate connector C-16, and repair if necessary.
- Check earthing line for open circuit.
Q: Is the check result normal?
YES:
Go to Step 8 .NO: Repair.
)
Q: Is the check result normal?
YES:
Go to Step 10 .NO: Repair.
- Check output line for open/short circuit and damage.
Q: Is the check result normal?
YES:
Go to Step 11 .NO: Repair.
Q: Is the check result normal?
YES:
Go to Step 12 .NO: Repair.
NOTE: Before checking harness, check intermediate connector C-17, and repair if necessary.
- Check power supply line for damage.
Q: Is the check result normal?
YES:
Go to Step 13 .NO: Repair.