Pinpoint Test A: No Communication With The Navigation System Module

WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK THE RECORDED DTCS FROM THE DRIVER DOOR MODULE
- Check the recorded results from the driver door module self-test.
- Are any DTCs recorded?
- Yes : If DTC B2359, refer to GLASS, FRAMES AND MECHANISMS to continue diagnosis of DTC B2359.
- No : GO to A2.
A2 CHECK CIRCUITS 30-GK8 (RD/BK) AND 10-GK8 (GY/BK) 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 30-GK8 (RD/BK), harness side and ground; and between the navigation system module C4209-2, circuit 10-GK8 (GY/BK), harness side and ground.
  
  Fig 1: Checking Circuits 30-GK8 (RD/BK) And 10-GK8 (GY/BK) For Voltage
  Courtesy of FORD MOTOR CO.
- Are the voltages greater than 10.5 volts?
- Yes : GO to A3.
- No : REPAIR the circuit in question. TEST the system for normal operation.
A3 CHECK CIRCUIT 31-GK8 (BK/RD) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between the navigation system module C4209-13, circuit 31-GK8 (BK/RD), harness side and ground.
  
  Fig 2: Checking Circuit 31-GK8 (BK/RD) For Open
  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. TEST the system for normal operation.