Pinpoint Test E: Navigation System Does Not Operate Correctly - The Display Screen Is Inoperative

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

E1 CHECK THE RECORDED DTCS FROM THE NAVIGATION SYSTEM MODULE
- Use the recorded results from the navigation system module self-test.
- Are any DTCs recorded?
- Yes : For DTC B2208, GO to PINPOINT TEST I to diagnose the controller area network (CAN) circuits. For all other DTCs, REFER to the NAVIGATION SYSTEM MODULE DIAGNOSTIC TABLE CODE (DTC) INDEX .
- No : GO to E2.
E2 CHECK THE AUDIO UNIT BUTTONS
- Press the MAP, AUDIO, DEST, and MENU buttons.
  
  Fig 1: Pressing MAP, AUDIO, DEST, and MENU Buttons
  Courtesy of FORD MOTOR CO.
- Does the display screen operate correctly?
- Yes : The system is operating correctly at this time. The concern may have been caused by SCREEN OFF selection on MENU screen.
- No : GO to E3.

E3 CHECK THE VIDEO AND SYNCHRONIZATION CIRCUITS FOR AN OPEN AND A SHORT TO GROUND

Key in OFF position.
Disconnect: Audio Unit C2253b.
Disconnect: Navigation System Module C4209.

Measure the resistances between the navigation system module C4209 pins harness side and the audio unit C2253b pins harness side; and between the navigation system module C4209 pins harness side and ground as follows:

AUDIO UNIT PIN SPECIFICATION

Navigation System Module Pin	Audio Unit Pin	Circuit
C4209 pin 8	C2253b pin 1	1534 (BK)
C4209 pin 9	C2253b pin 8	1536 (BK)
C4209 pin 10	C2253b pin 3	1538 (YE/RD)
C4209 pin 21	C2253b pin 2	1535 (BK)
C4209 pin 22	C2253b pin 9	1537 (RD)

Fig 2: Measuring Resistances Between Navigation System Module C4209 Pins Harness Side And Audio Unit C2253b Pins Harness Side; And Between Navigation System Module C4209 Pins Harness Side And Ground

Courtesy of FORD MOTOR CO.

Are the resistances less than 5 ohms between the navigation system module and the audio unit, and greater than 10,000 ohms between the navigation system module and ground?

Yes : GO to E4.
No : REPAIR the circuit in question. TEST the system for normal operation.

E4 CHECK THE VIDEO AND SYNCHRONIZATION CIRCUITS FOR A SHORT TO BATTERY

Key in ON position.

Measure the voltage between the navigation system module C4209 pins harness side and ground as follows:

NAVIGATION SYSTEM MODULE PIN SPECIFICATION

Navigation System Module Pin	Circuit
C4209 pin 8	1534 (BK)
C4209 pin 9	1536 (BK)
C4209 pin 10	1538 (YE/RD)
C4209 pin 21	1535 (BK)
C4209 pin 22	1537 (RD)

Fig 3: Measuring Voltage Between Navigation System Module C4209 Pins Harness Side And Ground

Courtesy of FORD MOTOR CO.

Is any voltage indicated?

Yes : REPAIR the circuit the question. TEST the system for normal operation.
No : GO to E5.

E5 SUBSTITUTE THE AUDIO UNIT
- Substitute a known good audio unit.
- Does the screen display appear?
- Yes : REMOVE the audio unit and SEND it to an authorized Ford audio system repair facility. TEST the system for normal operation.
- No : REINSTALL the original audio unit. GO to E6.
E6 CHECK FOR CORRECT NAVIGATION SYSTEM MODULE OPERATION
- Disconnect all the navigation system module connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the navigation system module connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new navigation system module. REFER to NAVIGATION SYSTEM MODULE . TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.