Lower Limit

Checking Mass Air Flow Sensor
- Ignition on.
- Connect a voltmeter between mass air flow (MAF) sensor connector terminals 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 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 (DTC).





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

Yes:
^ Proceed to test step below.

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

Checking Canister Purge Valve
- Remove hose to the intake manifold from the canister purge (CP) valve. Reinstall hose after fault-tracing. When installing use pliers 981 4215 and a new hose clamp.
- Connect vacuum pump 999 5843 to canister purge valve connector.
- Pump up a vacuum. The vacuum gauge should indicate a steady vacuum.

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

If reading is incorrect:
^ Try a new canister purge valve. Then continue by Erasing diagnostic trouble codes and resetting long-term fuel trim.





Checking Engine Oil Level
- Check engine oil level
- The oil level should be between the MIN and MAX marks.

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

If reading is incorrect:
^ Ensure that the oil level is correct.





Checking Engine Oil
- Start the engine and idle it for a few minutes.
- Go into scrolling values list.
- Read off and note short-term fuel trim value.
- Disconnect and plug crankcase ventilation.
- Read off the short-term fuel trim value again.
- This value should be more or less the same.

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

If reading is incorrect:
^ This indicates that the engine oil is contaminated with fuel. Change engine oil and oil filter. Continue by 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.

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.