Possible Causes

This DTC uses two-trip detection logic. DTC is set when heated oxygen sensor (B1 S2) output voltage remains at 0.45 volt or more, or 0.55 volt or less with vehicle at 25 MPH or more with engine at normal operating temperature. Possible causes are:

• Heated oxygen sensor (B1, S2) circuit is open or shorted.
• Defective heated oxygen sensor (B1, S2).