Possible Fault Causes
Sensor not active. Open IA wire. Catalytic converter plugged (rich exhaust gas at oxygen sensor in overrun cutoff mode); oil or gasoline in exhaust gas during overrun cutoff OR: Open circuit in trim wire.
Sensor not active. Open IA wire. Catalytic converter plugged (rich exhaust gas at oxygen sensor in overrun cutoff mode); oil or gasoline in exhaust gas during overrun cutoff OR: Open circuit in trim wire.