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Home >> Mercury >> 2008 >> Milan Base, 3.0 1, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 973 (Information System And Entertainment System) >> Diagnostic Tests >> Information and Entertainment System - Navigation >> Pinpoint Tests >> Pinpoint Test L: Loud Popping Sound When Cycling The Ignition >> Pinpoint Test L: Loud Popping Sound When Cycling The Ignition

Pinpoint Test L: Loud Popping Sound When Cycling The Ignition

WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
  1. L1 CHECK THE SUBWOOFER 
    • Key in OFF position.
    • Disconnect: Subwoofer Amplifier C466
    • Start the vehicle.
    • Is the symptom still present? 
    1. YES  : Go to  L2.
    2. NO  : Go to  L3.
  2. L2 CHECK THE AUDIO UNIT 
    • Key in OFF position.
    • Disconnect: Powertrain Control Module (PCM) Relay C1016
    • Key in START position.
      • Fig 1: Checking Circuit For Voltage
      GF0025907Courtesy of FORD MOTOR CO.
    • Measure the voltage between the subwoofer amplifier C466-1, circuit 174 (GY/BK), harness side and ground.
    • Is any voltage present? 
    1. YES  : Go to  L3.
    2. NO  : REMOVE the subwoofer amplifier. REFER to Subwoofer Amplifier . SEND it to an authorized audio system repair facility. TEST the system for normal operation after the repair.
  3. L3 CHECK CIRCUIT 1786 (BN/PK) FOR VOLTAGE 
    • Key in OFF position.
    • Disconnect: Audio Unit C229c
    • Disconnect: PCM Relay C1016
    • Key in START position.
      • Fig 2: Checking Circuit For Voltage
      GF0025924Courtesy of FORD MOTOR CO.
    • Measure the voltage between the audio unit C229e-7, circuit 1786 (BN/PK), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : SEND the audio unit to an authorized audio system repair facility. TEST the system for normal operation after the repair.
    2. NO  : Go to  L4.
  4. L4 CHECK CIRCUIT 1786 (BN/PK) FOR AN OPEN OR SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: SJB C2280e
      • Fig 3: Checking Circuit For Open Or Short To Ground
      GF0025932Courtesy of FORD MOTOR CO.
    • Measure the resistance between the audio unit C229e-7, circuit 1786 (BN/PK), harness side and the SJB C2280e-17, circuit 1786 (BN/PK), harness side; and between the audio unit C229e-7, circuit 1786 (BN/PK), harness side and ground.
    • Is the resistance less than 5 ohms between the SJB and the audio unit, and greater than 10,000 ohms between the audio unit and ground? 
    1. YES  : Go to  L5.
    2. NO  : REPAIR the circuit. TEST the system for normal operation.
  5. L5 CHECK FOR CORRECT SJB OPERATION 
    • Key in OFF position.
    • Disconnect all the SJB connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the SJB connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new SJB. REFER to MULTIFUNCTION ELECTRONIC MODULES article. TEST the system for normal operation.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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