2005 Ford Econoline E150, Van Cargo, 5.4 LFACTORY OEM SERVICE PROCEDURE

Pinpoint Test A: No Communication With The Vehicle Security Module

  1. A1 CHECK THE VOLTAGE TO THE VEHICLE SECURITY MODULE 
    • Key in OFF position.
    • Disconnect: Vehicle Security Module C203a.
    • Disconnect: Vehicle Security Module C203b.
    • Key in ON position.
    • Measure the voltage between the vehicle security module C203a-12, circuit 517 (BK/WH), harness side and ground; and between the vehicle security module C203b-25, circuit 640 (RD/YE), harness side and ground.
      Fig 1: Measuring Voltage Between Vehicle Security Module Circuit 517 And Ground
      G03890623Courtesy of FORD MOTOR CO.
    • Are the voltages greater than 10 volts? 
    • Yes  : GO to A2.
    • No  : REPAIR the circuit(s) in question. CLEAR the DTCs. REPEAT the self-test.
  2. A2 CHECK THE GROUND CIRCUITS FOR AN OPEN 
    • Key in OFF position.
    • Measure the resistance between the vehicle security module C203a-13, circuit 1205 (BK), harness side and ground; and between the vehicle security module C203b-14, circuit 57 (BK), harness side and ground.
      Fig 2: Measuring Resistance Between Vehicle Security Module Circuit 1205 And Ground
      G03890624Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 
    • Yes  : REFER to MODULE COMMUNICATIONS NETWORK to continue communication diagnostics.
    • No  : REPAIR the circuit(s) in question. CLEAR the DTCs. REPEAT the self-test.
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  • • You are missing required tools, torque specs, or safe lifting equipment.
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