1.CHECK FUSE Check for blown fuses.

Power source | Fuse No.
Battery | 8

Is the inspection result normal?
YES>>GO TO 2.
NO>>Be sure to eliminate cause of malfunction before installing new fuse.
2.CHECK POWER SUPPLY CIRCUIT
Check voltage between woofer harness connector and ground.

Signal name | Connector No. | Terminal No. | Ignition switch position | Voltage (Approx.)
Battery power supply | B18 | 9 | OFF | Battery voltage

Is the inspection result normal?
YES>>INSPECTION END
NO>>Check harness between audio amp. and fuse.