Pinpoint Test E: The Subwoofer Is Inoperative

WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

E1 CARRY OUT THE SPEAKER WALK-AROUND TEST - CHECK SUBWOOFER OPERATION
- Key in ON position.
- Turn on the audio unit.
- Carry out the speaker walk-around test by pressing preset buttons 3 and 6 simultaneously.
- Does the subwoofer sound operate correctly?
Yes

The system is operating

OK.

No

GO to E2.
E2 CHECK CIRCUIT 168 (RD/BK) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Subwoofer Amplifier C466.
- Key in ON position.
- Measure the voltage between the subwoofer amplifier C466-1, circuit 168 (RD/BK), harness side and ground.
  
  Fig 1: Checking Circuit 168 (RD/BK) Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 4.1 volts?
Yes

GO to E3.

No

GO to E7.
E3 CHECK CIRCUIT 37 (YE) FOR VOLTAGE
- Key in OFF position.
- Measure the voltage between the subwoofer amplifier C466-6, circuit 37 (YE), harness side and ground.
  
  Fig 2: Checking Circuit 37 (YE) Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes

GO to E4.

No

REPAIR the circuit. TEST the system for normal operation.
E4 CHECK CIRCUIT 1204 (BK/OG) FOR AN OPEN
- Measure the resistance between the subwoofer amplifier C466-2, circuit 1204 (BK/OG), harness side and ground.
  
  Fig 3: Checking Circuit 1204 (BK/OG) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes

GO to E5.

No

REPAIR the circuit. TEST the system for normal operation.
E5 CHECK CIRCUIT 172 (LB/RD) FOR AN OPEN OR SHORT TO GROUND
- Disconnect: Audio Unit C290c.
- Measure the resistances between the subwoofer amplifier C466-8, circuit 172 (LB/RD), harness side and the audio unit C290c-2, circuit 172 (LB/RD), harness side; and between the subwoofer amplifier C466-8, circuit 172 (LB/RD), harness side and ground.
  
  Fig 4: Checking Circuit 172 (LB/RD) For Open Or Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms between the subwoofer amplifier and the audio unit and greater than 10,000 ohms between the subwoofer amplifier and ground?
Yes

GO to E6.

No

REPAIR the circuit. TEST the system for normal operation.
E6 CHECK CIRCUIT 167 (BN/OG) FOR AN OPEN OR SHORT TO GROUND
- Measure the resistances between the subwoofer amplifier C466-7, circuit 167 (BN/OG), harness side and the audio unit C290c-1, circuit 167 (BN/OG), harness side; and between the subwoofer amplifier C466-7, circuit 167 (BN/OG), harness side and ground.
  
  Fig 5: Checking Circuit 167 (BN/OG) For Open Or Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms between the subwoofer amplifier and the audio unit and greater than 10,000 ohms between the subwoofer amplifier and ground?
Yes

REMOVE the subwoofer amplifier and SEND it to an authorized audio system repair facility. TEST the system for normal operation.

No

REPAIR the circuit. TEST the system for normal operation.
E7 CHECK CIRCUIT 168 (RD/BK) FOR OPEN
- Measure the resistance between the subwoofer amplifier C466-1, circuit 168 (RD/BK), harness side and the audio unit C290c-4, circuit 168 (RD/BK), harness side.
  
  Fig 6: Checking Circuit 168 (RD/BK) Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes

REMOVE the audio unit and SEND it to an authorized audio system repair facility. TEST the system for normal operation.

No

REPAIR the circuit. TEST the system for normal operation.