Lexus NX 450h+ AZ20

This is a well-documented issue across the NX 450h+ and related Toyota PHEVs. The DC-DC converter (which replaces a traditional alternator) sometimes fails to charge the 12V battery sufficiently while driving, particularly during short trips or when the car runs mostly in EV mode. Owners report the car going completely dead after 7-10 days of being parked. The root cause is the DC-DC converter being turned off for extended periods while the car is in drive mode. Symptoms include random electrical faults, door handles not responding, and inability to start. A quality AGM replacement battery costs €150-250, and some owners add a trickle charger (CTEK recommended) for extended parking periods. Lexus has issued software updates for the charging logic, but the underlying issue persists for many owners.

The new-generation Lexus multimedia system introduced with the AZ20 NX has been widely reported to freeze, crash, and reboot during driving. When it crashes, the entire system can become unusable for the remainder of the journey, including navigation, climate controls, and the reversing camera display. Lexus has released several over-the-air software updates, which resolved the issue for some owners but not all. In persistent cases, the entire head unit may need replacement under warranty (€500-800 if out of warranty). The problem is most common on 2022 models and has improved with subsequent software versions.

The NX AZ20 uses electronic door handles (e-latch) that can fail to open, particularly in cold weather when water enters the handle mechanism and freezes. Lexus issued a Limited Service Campaign in some markets to replace affected exterior door handle assemblies. Symptoms include the button clicking but the door not unlatching, or a door lock malfunction warning on the dashboard. A mechanical backup exists (pulling the interior handle twice). Replacement of a single door handle assembly costs €200-300 at a dealer. The issue is most pronounced in regions with frequent freeze-thaw cycles.

The A25A-FXS engine shares a known EGR cooler vulnerability with other Toyota Dynamic Force engines. Traces of chlorine in the coolant or production residue gradually corrode the cooler internally, allowing coolant to enter the intake manifold and combustion chambers. Symptoms include a sweet coolant smell, dropping coolant level without visible external leaks, 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. Because the NX 450h+ runs in EV mode for much of its urban driving, engine operating hours accumulate more slowly than on a conventional hybrid, potentially delaying onset. Repair cost is €500-1,200 at a specialist.

Some owners report a check engine light accompanied by a 'Plug-in Charging System Malfunction' message. The issue can be intermittent, disappearing and returning over weeks. In some cases, a dealer software update resolves the problem. In others, the onboard charger module may need replacement, which costs approximately €1,000-1,500 out of warranty. The 6.6 kW onboard charger is generally reliable, but occasional failures have been reported, particularly on early 2022 models. If the warning appears, the car can still drive normally in hybrid mode.

Special Service Campaign 23LC01 addresses a software bug in the forward recognition camera on 2022-2023 NX models. The Lexus Safety Sense+ features (pre-collision system, lane departure alert, adaptive cruise control) can become inoperative for approximately 4 seconds before rebooting. The fix is a free dealer software update that takes around 30-45 minutes. A separate TSB (25LC02) addresses a rarer issue where the software bug can physically damage the camera, requiring replacement at approximately €200-300.