Patent ID: 8268147

Claim:
A control method for a gas sensor, the gas sensor having a sensor element formed with at least one electrochemical cell to detect the concentration of a specific gas component in measurement gas, the control method comprising: receiving a mode command to specify one of a plurality of sensor energization modes including at least a gas concentration detection mode, a protection mode and a pre-energization mode; switching the sensor element into said one of the plurality of sensor energization modes according to the mode command; judging satisfaction of a certain condition where the mode command is to specify the gas concentration detection mode and the sensor element is in any of the plurality of sensor energization modes other than the pre-energization mode at the time of receipt of the mode command; and at the time of receipt of the mode command specifying switching of the electrochemical cell of the sensor element to the gas concentration detection mode, prohibiting the sensor element from switching over to the gas concentration detection mode if the sensor element is in the protection mode and switching the sensor element to the gas concentration detection mode if the sensor element is in the pre-energization mode.