Patent ID: 7100368

Claim:
A drive device for a secondary air injection system including a motor-type air pump and an electromagnetic valve for introducing the secondary air into the exhaust gas passage upstream of a catalyst for purifying the exhaust gas of an internal combustion engine, and first and second semiconductor switching elements for separately controlling the supply of electric current to the air pump and to the electromagnetic valve, said drive device for the secondary air injection system comprising: signal-processing means for operating said first and second semiconductor switching elements upon receiving an instruction signal from a high-order system; abnormal condition detector means for detecting abnormal conditions in the operation for controlling the air pump and the electromagnetic valve; self-protection means for effecting a predetermined self-protecting control operation based on the result detected by the abnormal condition detector means; and signal output means for sending, to the high-order system, a diagnosis signal representing the condition of a load controlled by the signal-processing means and by the self-protection means.