A heater control device for an air-fuel ratio sensor.

摘要

A heater control device for an air-fuel ratio sensor which comprises: an air-fuel ratio sensor comprising a sensor element which detects an air-fuel ratio state of exhaust gas of an engine, and a heater (32) which heats the sensor elements; a heater current flow control means for controlling a value of a resistance (Rh) of the heater (32) to be a target resistance value; a harness (20) having a couple of couplers (20C) at both ends thereof which connects between the air-fuel ratio sensor and the heater current flow control means; and a current detecting resistance which is incorporated in the coupler (20C) on the air-fuel ratio sensor side, or provided adjacent to said coupler (20C) on the air-fuel ratio sensor side, and which is connected to the heater (32) in series and detects current of the heater. <IMAGE>