Navigation System Symptom Troubleshooting - Picture has lines/rolls/other issues

Picture has lines/rolls/other issues NOTE: Always check the connectors for poor connections or loose terminals. Before troubleshooting, get the navigation system anti-theft codes. After troubleshooting, enter the navigation system anti-theft codes. Check for electronic aftermarket accessories (possibly hidden) mounted near the display unit or the navigation unit. Are there any electronic accessories?
YES | - | Disable the accessories, and recheck.■
NO | - | Go to Step 2 .
Start up the navigation picture. Is the picture scrolling horizontally (left to right or right to left)?
YES | - | Check for an open or short to ground in the C SIG wire from navigation unit connector A (20P) terminal No. 12 to display unit connector B (20P) terminal No. 19. Also check for a short to ground between display unit connector B terminal No. 19 and terminal No. 20.■
NO | - | Go to Step 3 .
Go into the Diagnostic mode and use ‘‘RGB Color'' test under Monitor Check. Is the picture missing a red, green or blue color?
YES | - | Do the troubleshooting for the picture is missing a color or tone. ■
NO | - | Go to Step 4 .
Turn the ignition switch OFF. Substitute a known-good display unit, and recheck. Is the picture OK?
YES | - | Replace the original display unit.■
NO | - | Replace the navigation unit. ■