Pinpoint Test A: No Communication With The Vehicle Security Module

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?

A2 CHECK THE VEHICLE SECURITY MODULE GROUND CIRCUIT

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 communication diagnostics.
No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.