Visually/physically inspect the following items:

- Vacuum hoses for splits, kinks and improper connections.

- Exhaust system between HO2S and Three way catalyst for air leakage

- Intake manifold leak

- Throttle body gasket leak

- Gasket between intake manifold and surge tank leak

- Clog or contamination of intake manifold and injector by foreign materials

- Contamination and open stuck between surge tank and PCSV by foreign materials

- PCV hose for proper installation

Was a problem found in any of the above areas?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Visual/Physical Inspection" procedure.

Visually/physically inspect the following items:

- Ensure that the HO2S is securely installed.

- Check for corrosion on terminals

- Check for terminal tension ( at the HO2S and at the ECM/PCM)

- Check for damaged wiring

- Check the HO2S ground circuit for a good connection

Was a problem found in any of the above areas?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Check Fuel Line" procedure.

Check Clog, contamination and installation of Fuel Line as follows.

- Connection for each connectors in fuel line

- Damage, interference and installation of vaccum hose connected to fuel line

- Bend, leakage and squeeze of pipe in fuel line

Was a problem been found?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Check Fuel Pressure" procedure.

IG "OFF"

Connect fuel pressure gauge on the fuel filter with fuel pressure gauge adaptor.

Start engine again and measure fuel pressure.

Ws the fuel pressue normal?

	▶ If no problems were found, replace the HO2S(S1).
	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.