Pinpoint Test B: No Communication With The Navigation System Module

WARNING: This page is about a different car, the 2004 Lincoln Aviator. However, it is still accessible from the selected car via links, so may be relevant.

B1 CHECK CIRCUITS AND 1001 (WH/YE) 1002 (BK/PK) FOR VOLTAGE

Key in OFF position.
Disconnect: Navigation System Module C4209.
Key in ON position.
Measure the voltage between the navigation system module C4209-1, circuit 1001 (WH/YE), harness side and ground; and between the navigation system module C4209-2, circuit 1002 (BK/PK), harness side and ground.

Fig 1: Checking Circuits And 1001 (WH/YE) 1002 (BK/PK) For Voltage
Courtesy of FORD MOTOR CO.
Are the voltages greater than 10.5 volts?

Yes

GO to B2.

REPAIR the circuit in question. TEST the system for normal operation.

B2 CHECK CIRCUIT 1205 (BK) FOR AN OPEN

Key in OFF position.
Measure the resistance between the navigation system module C4209-13, circuit 1205 (BK), harness side and ground.

Fig 2: Checking Circuit 1205 (BK) For An Open
Courtesy of FORD MOTOR CO.
Is the resistance less than 5 ohms?

Yes

REFER to MODULE COMMUNICATIONS NETWORK to continue communication diagnostics.

REPAIR the circuit. TEST the system for normal operation.