Pinpoint Test A: No Communication With The Navigation System Module

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

Test Step

A1 CHECK CIRCUITS 828 (VT/LB) AND 1523 (DG) FOR VOLTAGE

Key in OFF position.
Disconnect: Navigation System Module C4209.
Key in ON position.
Measure the voltage between the navigation system module C4029 pin 1, circuit 828 (VT/LB), harness side and ground; and between the navigation system module C4029 pin 2, circuit 1523 (DG), harness side and ground.

Fig 1: Checking Circuits 828 (VT/LB) And 1523 (DG) For Voltage
Courtesy of FORD MOTOR CO.
Are the voltages greater than 10.5 volts?

Result / Action to Take

Yes

GO to A2.

REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

Test Step

A2 CHECK CIRCUIT 694 (BK/LG) FOR AN OPEN

Key in OFF position.
Measure the resistance between the navigation system module C4209 pin 13, circuit 694 (BK/LG), harness side and ground.

Fig 2: Checking Circuit 694 (BK/LG) For An Open
Courtesy of FORD MOTOR CO.
Is the resistance less than 5 ohms?

Result / Action to Take

Yes

REFER to MODULE COMMUNICATIONS NETWORK to continue communication diagnostics.

REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.