| 1. | With the ignition switch ON (II), push the power switch ON to see if audio unit turns ON. Does the audio unit operate and sound properly? YES - Intermittent failure, the system is OK at this time.n NO - Go to  2. | 
| 2. | Turn the ignition switch OFF. | 
| 3. | Check the No. 23 (10 A) fuse in the uncler-hood fuse/relay box and No. 35 (7.5 A) fuse in the under-dash fuse/relay box. Are the fuses OK? YES - Go to  4. NO - Replace the fuse, and recheck.n | 
| 4. | Remove the audio unit. Check that the audio unit is properly connected. Is it connected properly? YES - Go to  5. NO - Reconnect the connector, and recheck the function.n | 
| 5. | Disconnect audio unit connector A (17P). | 
| 6. | Turn the ignition switch ON (II). | 
| 7. | Measure the voltage between audio unit connector A (17P) terminal No. 14 and body ground, and between terminal No. 17 terminals and body ground. 
 Is there battery voltage on both terminals? YES - Go to  8. NO - Repair open in the wire(s) between the No. 23 (10 A) fuse in the under-hood fuse/relay box and  No. 35 (7.5 A) in the under-dash fuse/relay box and the audio unit.n | 
| 8. | Check for voltage between audio unit connector A (17P) No. 9 terminal and body ground. 
 Is there less than 0.1 V? YES - Replace the audio unit.n NO - Repair open in the wire between audio unit connector A (17P) No. 9 terminal and body ground (G505).n |