Methods and systems for operating an exhaust oxygen sensor based on water contact at the sensor

An engine method, comprising:

• indicating water at an exhaust oxygen sensor positioned in an engine exhaust passage based on a sensor parameter of the exhaust oxygen sensor while operating the exhaust oxygen sensor in a variable voltage (VVs) mode where a reference voltage is adjusted from a lower, first voltage to a higher, second voltage;
• adjusting one or more of sensor operation and engine operation based on the indicating water, wherein the sensor parameter includes a pumping current of the exhaust oxygen sensor when the exhaust oxygen sensor is operated at the second voltage;
• and
• indicating water at the exhaust oxygen sensor in response to the pumping current of the exhaust oxygen sensor being higher than a threshold current, and wherein the adjusting the exhaust oxygen sensor operation incudes operating the exhaust oxygen sensor in the VVs mode until the pumping current falls below the threshold current.