Pinpoint Test A: No Communication With The Vehicle Security Module

WARNING: This page is about a different car, the 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the flex probe kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

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-3, circuit 1306 (PK/WH), harness side and ground; and between the vehicle security module C2113b-1, circuit 116 (RD/BK), harness side and ground.
  
  Fig 1: Checking Voltage To Vehicle Security Module
  Courtesy of FORD MOTOR CO.
- Are the voltages greater than 10 volts?
Yes : GO to A2.

No : VERIFY the central junction box (CJB) fuses 19 (10A) and 102 (30A) are OK. If OK, REPAIR the circuit(s) 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-14, circuit 57 (BK), harness side and ground.
  
  Fig 2: Checking 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.