Pinpoint Test G: Loud Popping Sound When Cycling The Ignition

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: For vehicles built through 8/2005, whenever power is disconnected (through the battery or through disconnecting the connector) from the CD6 audio unit, then reconnected, the power must be continuous for a minimum of 25 seconds. Failure to follow this instruction may result in permanent damage to the audio unit.

G1 CHECK CIRCUIT CBP13 (GY/BN) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Audio Unit C290a or C240a.
- Disconnect: Starter Relay.
- Key in START position.
- Measure the voltage between the audio unit C290a-15 or C240a-15, circuit CBP13 (GY/BN), harness side and ground.
  
  Fig 1: Checking Circuit CBP13 (GY/BN) For Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes : For the Audiophile audio system, GO to G2.

For the THX® audio system, GO to G3.

For all others, SEND the audio unit to an authorized audio system repair facility. TEST the system for normal operation after the repair.

No : VERIFY the smart junction box (SJB) fuse 22 (7.5A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.
G2 ISOLATE THE SUBWOOFER AMPLIFIER
- Key in OFF position.
- Connect: Audio Unit C290a.
- Disconnect: Subwoofer Amplifier C466a.
- Cycle the key through all of the ignition switch positions.
- Is a loud popping sound present?
Yes : REMOVE the audio unit and SEND it to an authorized audio system repair facility. REFER to AUDIO UNIT - FUSION, MILAN or AUDIO UNIT - ZEPHYR . TEST the system for normal operation after the repair.

No : INSTALL a new subwoofer amplifier. REFER to SUBWOOFER AMPLIFIER . TEST the system for normal operation.
G3 ISOLATE THE LH AUDIO AMPLIFIER
- Key in OFF position.
- Connect: Audio Unit C240a.
- Disconnect: LH Audio Amplifier C4324b.
- Cycle the key through all of the ignition switch positions.
- Is a loud popping sound present?
Yes : GO to G4.

No : INSTALL a new LH audio amplifier. REFER to AUDIO AMPLIFIER . TEST the system for normal operation.
G4 ISOLATE THE RH AUDIO AMPLIFIER
- Key in OFF position.
- Disconnect: RH Audio Amplifier C4325b.
- Connect: LH Audio Amplifier C4324b.
- Cycle the key through all of the ignition switch positions.
- Is a loud popping sound present?
Yes : REMOVE the audio unit and SEND it to an authorized audio system repair facility. REFER to AUDIO UNIT - ZEPHYR . TEST the system for normal operation after the repair.

No : INSTALL a new RH audio amplifier. REFER to AUDIO AMPLIFIER . TEST the system for normal operation.