Abstract: Apparatus for use in conjunction with a vehicular engine, such as a large truck Diesel engine. The apparatus includes sensing elements responsive to respective engine operating conditions for providing signals when the respective conditions are adverse to the proper operation of the engine. When such a signal is generated, two things occur. First, a warning indication is given to the driver of the vehicle. Second, a timer is started. At the termination of the timing interval, the engine is disabled. This allows the driver of the vehicle time to pull it off the road in the event an engine malfunction occurs. There is further provided an override switch, the momentary operation of which restarts the timer in order to give the driver additional time.