Toyota Sienna slipping out of AWD into 2-wheel drive after computer reset on Toyota Sienna

Some Toyota Sienna owners report experiencing issues with the all-wheel drive (AWD) system slipping into two-wheel drive mode after a computer reset, which may indicate a malfunction in the AWD system. These problems can stem from electrical disruptions that occur post-reset, potentially leading to erratic power distribution or drivetrain failure. To diagnose these issues, some owners find it necessary to use an OBD-II scanner to read fault codes and check for warning messages indicating that "2WD mode engaged." Additionally, inspecting components such as the AWD Control Module, sensors, and software may reveal faults contributing to the problem. Understanding the different drivetrain options in the Toyota Sienna can also aid in identifying how these issues may arise.