Pinpoint Test A: No Communication With The Vehicle Security Module

WARNING: This page is about a different car, the 2005 Lincoln Navigator and 2005 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK THE VOLTAGE TO THE VEHICLE SECURITY MODULE
- Key in OFF position.
- Disconnect: Vehicle Security Module C2113b.
- Key in ON position.
- Measure the voltage between the vehicle security module C2113b pin 3, circuit 729 (RD/WH), harness side and ground; and between the vehicle security module C2113b pin 1, circuit 1523 (DG), harness side and ground.
  
  Fig 1: Measuring Voltage Between Vehicle Security Module C2113B Pin 3 Circuit 729 (RD/WH)
  Courtesy of FORD MOTOR CO.
- Are the voltages greater than 10 volts?
- Yes : GO to A2.
- No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
A2 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Key in OFF position.
- Disconnect: Vehicle Security Module C2113a.
- Measure the resistance between the vehicle security module C2113a pin 14, circuit 57 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between Vehicle Security Module C2113A Pin 14 Circuit 57 (BK)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : REFER to MODULE COMMUNICATIONS NETWORK to continue communication diagnosis.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.