The LX470 was very bouncy even just driving down a smooth street, although 4 new shocks had been installed recently. The car failed to rise or lower when the AHC switch button was pushed and the AHC Hi or Lo light was blinking, indicating a problem with the air suspension system.
All that pointed to that at least one of the AHC suspension accumulators has failed.
Since this car has 200k mi with the original suspension accumulators, which are designed to last 100k mi, the accumulators are due for replacement.