Making its debut in 2004, the Infiniti QX56 is the Nissan luxury line's full-size luxury SUV and the first Infiniti car assembled in North America. Below are the common problems associated with the vehicle, particularly during its first generation (2004 to 2008).
Issues regarding the debut model include faulty cruise control due to maladjustment of the switch on the brake pedal, and possible accelerated tire wear due to a broken O-ring for the tire pressure monitoring system transmitter. The 2004 model also faced engine knocking and stalling. The noise can be fixed with installing the revised service port fitting in the evaporative emissions control system, while the stalling can be resolved with a power distribution module replacement.
There are other problems that afflict 2004 entries. Transmission fluid may leak from the connections for the transmission cooler, and water getting into and corroding the connector between the engine control wiring harness and transmission wiring harness may cause the engine to either not crank, or crank but not start. In addition, the electrical system could be damaged or even start a fire due to a short if trailer wiring is connected wrong; and there could be occurrences of low power at wide-open throttle possibly caused by low fuel pressure.
There were persistent or potential problems in the 2005 model, carryovers from the previous years: transmission fluid and water leaks, and electrical system wiring shorts.
Nissan had a recall on Infiniti QX56s, as well as Nissan Titan and Armada vehicles, due to questionable sealing of air-conditioning condenser fan motors. This could cause excessive water intrusion and inadequate drainage or moisture, thus leading to corrosion and possible overheating. The installation of a "thermal protector kit"---or a replacement of the fan motor---was the remedy for the problem.
By the time the 2006 model arrived, Infiniti had already released fluid lines and clamps to resolve the transmission fluid leaks. The only significant persistent problem arises from low power at the vehicle's wide-open throttle.
No major problems have been reported for the 2007and 2008 entries.
