Abstract: A main CPU determines whether or not there is a request for one valve driving based on an engine operating state such as an engine speed and a load factor, with reference to a control map. When it is determined that there is a request for one valve driving, it is determined whether or not there is an overlapping period between opening periods. When it is determined that there is no overlapping period, a high speed control is performed for controlling electromagnetically driven valves. When it is determined that there is no request for one valve driving, or when it is determined that there is the overlapping period, a low speed control is performed for controlling electromagnetically driven valves.

Abstract: A main CPU determines whether or not there is a request for one valve driving based on an engine operating state such as an engine speed and a load factor, with reference to a control map. When it is determined that there is a request for one valve driving, it is determined whether or not there is an overlapping period between opening periods. When it is determined that there is no overlapping period, a high speed control is performed for controlling electromagnetically driven valves. When it is determined that there is no request for one valve driving, or when it is determined that there is the overlapping period, a low speed control is performed for controlling electromagnetically driven valves.

Abstract: A manual cut-off system makes it possible to manually change operability of each of a plurality of passive safety devices, including air bags. The system aims at accurately maintaining operability of each of the passive safety devices until the air bags are required to operate. If a multistage switch for changing operability of each of the passive safety devices, including air bags, assumes a position for preventing operation of predetermined ones of the passive safety devices, ignition signals are prevented from being outputted to squibs corresponding to those predetermined passive safety devices. A CPU detects a state of the multistage switch based on the voltage between a common contact and a connecting portion of resistors. The thus-detected state of the multistage switch is stored in an IC memory.

Abstract: A diagnostic circuit for checking a capacity of a backup condenser having a check circuit in which the clamp means includes a Zener diode and a transistor connected in parallel with the backup condenser and the current flowing through a charge resistor, the Zener diode and the transistor during a time B that the transistor is turned on by a microprocessor, results in the terminal voltage of the backup condenser to be clamped to a predetermined clamp voltage.