Pinpoint Test A: No Communication With The Vehicle Security Module

WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK VOLTAGE TO THE VEHICLE SECURITY MODULE
NOTE: The battery must be disconnected before disconnecting the vehicle security module connectors to prevent triggering the anti-theft alarm.
- Key in OFF position.
- Disconnect the battery. Refer to BATTERY, MOUNTING AND CABLES .
- Disconnect: Vehicle Security Module C2113b.
- Connect the battery. Refer to BATTERY, MOUNTING AND CABLES .
- Key in ON position.
- Measure the voltage between the vehicle security module C2113b pin 3, circuit 1306 (PK/WH), harness side and ground; and between the vehicle security module C2113b pin 1, circuit 116 (RD/BK), harness side and ground.
  
  Fig 1: Checking Voltage To The Vehicle Security Module
  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 THE VEHICLE SECURITY MODULE GROUND CIRCUIT
- Key in OFF position.
- Disconnect the battery. Refer to BATTERY, MOUNTING AND CABLES .
- Disconnect: Vehicle Security Module C2113a.
- Connect the battery. Refer to BATTERY, MOUNTING AND CABLES .
- Measure the resistance between the vehicle security module C2113a pin 14, circuit 57 (BK), harness side and ground.
  
  Fig 2: Checking The Vehicle Security Module Ground Circuit
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : REFER to MODULE COMMUNICATIONS NETWORK to continue diagnosis of the communication network.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.