A method and apparatus for controlling a diagnostic module for an exhaust gas sensor in a vehicle is provided. The exhaust gas sensor is located in an exhaust pathway in the vehicle. The diagnostic module may be configured to perform a signal range verification of an oxygen sensor portion of the exhaust gas sensor. A controller is operatively connected to the exhaust gas sensor and to the vehicle engine. The controller disables the diagnostic module when one or more entry conditions are satisfied. The entry conditions may include requiring the engine speed to be greater than a fuel cut-off threshold, the fuel cut-off threshold being the engine speed at which the fuel to the engine is terminated. The entry conditions may include: no fuel being delivered to the engine; and a vehicle exhaust brake mode being activated such that the exhaust pathway from the engine is obstructed.