Navigation System Symptom Troubleshooting - Voice guidance cannot be heard

Voice guidance cannot be heard NOTE: Always check the connectors for poor connections or loose terminals. Before troubleshooting, write down the customer's radio station presets, and get the radio and navigation system anti-theft codes. Press the display unit SET-UP button. Check the volume setting for the navigation system. Is it set to OFF?
YES | - | Set the volume to an audible level.■
NO | - | Go to Step 3 .
Check the radio operation. Can you hear the radio?
YES | - | Go to Step 4 .
NO | - | Troubleshoot the audio system.■
Go into the Diagnostic Menu and use the ‘‘Navi System Link'' test to check the radio. Is ‘‘Radio'' icon red?
YES | - | Troubleshoot the audio system.■
NO | - | Go to Step 5 .
Turn the ignition switch OFF. Disconnect the navigation unit connector B (14P) and the audio unit connector A (20P). Check for continuity between body ground and navigation unit connector B (14P) terminals No. 5, No. 12 individually. Is there continuity?
YES | - | Replace the affected shielded harness.■
NO | - | Go to Step 8 .

Check for continuity between navigation unit connector B (14P) terminal No. 5 and the audio unit connector A (20P) terminal No. 13. Is there continuity?
YES | - | Go to Step 9 .
NO | - | There is an open in the circuit between the navigation unit and audio unit. Check for poor connections or loose terminals at the audio and navigation units. If a poor connection or loose terminal is found, replace the affected shielded harness.■

Check for continuity between navigation unit connector B (14P) terminal No. 12 and the audio unit connector A (20P) terminal No. 12. Is there continuity?
YES | - | Go to Step 10 .
NO | - | There is an open in the circuit between the navigation unit and audio unit. Check for poor connections or loose terminals at the audio and navigation units. If a poor connection or loose terminal is found, replace the affected shielded harness.■
Substitute a known-good audio unit, and recheck. Is the system OK?
YES | - | Replace the original audio unit.■
NO | - | Replace the navigation unit. ■