Test NTC-7A - Checking Oxygen Sensor Switching
WARNING:
High fuel pressure may be present in fuel lines. Open fuel system with caution. See FUEL PRESSURE RELEASE .
- Allow engine to reach normal operating temperature. Using scan tool, read pre-catalyst/upstream and post-catalyst/downstream O2S states. Raise engine speed to more than 1500 RPM. If both O2S states are switching between rich and lean, system is functioning properly. Test is complete. If either or both O2S is locked on lean, perform TEST NTC-7B . If neither O2S is locked on lean, go to next step.
- Turn engine off. Release fuel pressure. Connect fuel pressure gauge to fuel rail. Turn ignition on. Using scan tool, actuate fuel system test. Allow fuel pressure gauge to stabilize to normal fuel pressure. Stop fuel system actuation test. Go to next step.
- Monitor fuel pressure gauge for one minute. If fuel pressure gauge reading drops more than 10 psi (0.7 kg/cm2 ), replace leaking injector(s) as necessary and perform TEST VER-2A. If fuel pressure gauge reading does not drop more than 10 psi (0.7 kg/cm2 ), go to next step.
- Inspect air cleaner and inlet ducts for restrictions. Repair air cleaner/inlet ducts as necessary and perform TEST VER-2A . If no restrictions exist, perform TEST NTC-8A .