Upper Limit

Checking Mass Air Flow Sensor
- Ignition on.
- Connect a voltmeter between mass air flow (MAF) sensor connector terminal 2 and 4.
- The voltmeter should read 0.1 - 0.2 Volts.

If reading is OK:
^ Proceed to test step below.

If reading is incorrect:
^ Try a new mass air flow sensor.





Checking For Air Leakage In The Intake System
- Check for any air leakage.
- Is there any air leakage?

No:
^ Proceed to test step below.

Yes:
^ Remedy as necessary. Continue by erasing diagnostic trouble code (DTC) and resetting long-term fuel trim.





Checking For Air Leakage In The Exhaust System
- Check for air leakage.
- Is there any air leakage?

No:
^ Proceed to test step below.

Yes:
^ Remedy as necessary. Continue by erasing diagnostic trouble code and resetting long-term fuel trim.





Checking Fuel And Residual Pressure
- Check fuel and residual pressure.
- Is fuel pressure OK?

Yes:
^ Proceed to test step below.

No:
^ Remedy as necessary. Then continue with: Erasing diagnostic trouble codes and resetting long-term fuel trim.





Connecting Test Box
- Connect the test box and check ground terminals.
- Connect engine control module.
- Check all signals to and from engine control module.
- Remedy as necessary.

Then continue with:
^ Fault corrected





Verification
- After carrying out the repair, check that the fault has been remedied as follows.
- Ignition off.
- Reconnect connectors and reinstall components.
- Go into scrolling value list.
- Read off the long-term fuel trim value.
- Test drive the car.
- Watch the long-term fuel trim value until it switches to completed.
- If EFI-231/232 is stored it should have the status intermittent fault.

Yes:
^ Fault corrected

No:
^ Proceed to test step below.

Fault-tracing Information
The verification result shows that the fault persists.

- Do you want to exit fault-tracing?

Yes:
^ Fault not corrected

No:
^ Return to Checking Mass Air Flow Sensor section above.