Lexus NX 350h AZ20

The A25A-FXS engine shares a known EGR cooler vulnerability with other Toyota Dynamic Force engines. Chlorine traces from coolant or production residue corrode the cooler internally over time, allowing coolant to enter the intake manifold and combustion chambers. Symptoms include a sweet coolant smell, low coolant level without visible external leak, and white exhaust smoke. Toyota has issued a Technical Service Bulletin for EGR cooler replacement. The issue typically appears after 80,000-120,000 km. Repair involves replacing the EGR cooler and sometimes the intake manifold, costing between €500 and €1,200 at a specialist. Using Toyota-specified Super Long Life Coolant and avoiding coolant mixing helps prevent this.

The second-generation NX's 14-inch infotainment system is a frequent complaint. Owners report the screen going black for 1-20 minutes, the system rebooting spontaneously, or navigation freezing entirely — sometimes requiring stopping and restarting the car. Lexus has released multiple software updates that partially address the issue but do not fully resolve it for all owners. A hard reset (holding the power button for 20 seconds) is a common workaround. In rare cases the head unit needs replacement (approximately €500). Most occurrences are covered under warranty if the car is within the 3-year factory period. The issue does not affect driving safety but loses access to climate controls, navigation, and audio during the blackout.

The NX 350h's DC-DC converter (which replaces a traditional alternator) does not charge the 12V battery when the car is in ACC mode or during remote start. Owners who frequently use accessory mode to listen to music while parked, or who leave the car unused for several days, find the 12V battery dead. This is a design characteristic shared with the RAV4 Hybrid and RX 350h. The car must be in READY mode for the traction battery to charge the 12V system. Battery replacement costs €150-250, but a software update from Lexus can reduce parasitic draw. Using a trickle charger (CTEK recommended) for extended parking periods prevents the issue.

Owners report persistent rattles from the driver-side dashboard near the AC vents, the center stack infotainment area, and the center console lid. The noise appears on rough or uneven road surfaces and is characterized as plastic-on-plastic contact. Some owners report that Lexus service dismantled the dashboard and wrapped components in felt, but the rattle returned within weeks. The issue varies between individual cars — some NX 350h owners report no rattles at all. Lexus has not issued a formal fix. While not a mechanical concern, it undermines the premium ownership experience and can affect resale value if noticeable during a test drive.

In cold climates (below -10 degrees C), the rubber push-button mechanism on the door handles can freeze, preventing the doors from opening. This affects both the driver and passenger doors, and sometimes the fuel door as well. Lexus acknowledges the problem as a known characteristic. Workarounds include entering through an unfrozen door or warming the handle area. Some dealers have replaced door handle assemblies under warranty, though the replacement may also freeze. Applying silicone spray to the handles before winter can help prevent the issue. This primarily affects owners in Scandinavia, northern Germany, and Alpine regions.

Multiple NX owners report that all 20 factory wheel bolts rust significantly within the first 6-12 months, even in mild climates. The corrosion appears to be a coating quality issue from the factory. If left untreated, bolts can seize, making wheel removal difficult during tire changes. Replacement of all 20 bolts costs approximately €150-400 depending on whether dealer or aftermarket bolts are used. Lexus is aware of the issue but has not issued a recall. Applying anti-seize compound during tire changes is recommended. Some owners preemptively replace with aftermarket stainless or coated bolts.