Possible Causes

This DTC uses two-trip detection logic. DTC is set when heated oxygen sensor (B1, S1) voltage remains at 0.42 volt or more, or 0.48 volt or less with engine idling and at normal operating temperature. Possible causes are:

• Heated oxygen sensor (B1, S1) circuit is open or shorted.
• Defective heated oxygen sensor (B1, S1).
• Air induction system malfunction.
• Improper fuel pressure.
• Defective fuel injector.
• Defective ECM.