Check for continuity between the terminals shown of the Hands Free Telephone control unit 28P connector and the navigation unit connector C (16P).
Is there continuity?
YES
-
Substitute a known-good Hands Free Telephone control unit, then recheck. If the symptom goes away, replace the original Hands Free Telephone control unit. If the symptom does not go away, replace the faulty navigation unit.■
NO
-
Replace the faulty harness between the Hands Free Telephone control unit and the navigation unit.■