There are 1 owner-reported powertrain & transmission complaints for the 2006 Lexus RXin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
This vehicle seems to have a well-documented problem with water intrusion that damages the ECU and hybrid battery. The 2006 and 2007 RX400h has the HV battery located under the seat, which is the low spot in the rear section of the car. If water is spilled or the body has a water leak, the water will pool at the center of the battery. Lexus considered this, and added a drain under the battery, but the drain has a filter, presumably to keep insects out, and the filter is easily clogged. This, coupled with a pattern problem of split body seams near the rear hatch strut mount causing a water leak in the rear of the car, has created isolation faults in many of the RX400h SUVs. The condition presents as warnings on the instrument cluster and a no-start condition where the vehicle is inoperable. A search for "lexus ECU water intrusion" brings up my vehicle's exact model and year so this is well-documented.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026