| 摘要 |
<p>PROBLEM TO BE SOLVED: To reliably diagnose a short circuit failure without adding a circuit component to a conventional circuit and without increasing the cost. SOLUTION: In a failure diagnostic mode, a CPU 11 feeds a weak diagnostic current to a plurality of squibs DR1, DR2 respectively to self-diagnose the healthiness of the squibs based on the 'H' or 'L' of their both end voltages respectively. The CPU 11 feeds a diagnostic current to one of squib lines 15, 16 feeding power to the squibs on the downstream side or on the upstream side not connected in common to the squib line to the other squib, compares both end voltages of the squib receiving the diagnostic current and the other squib, and judges that a short circuit occurs on the squib lines when they are nearly equal.</p> |
