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You need to tow it to and have it inspected by an independent hybrid shop or Toyota specialist. Use Google and Yelp to find shops nearby. I would not use a dealer.
In general:
The diagnosis code DSS1 in a Toyota vehicle indicates that the Driving Support System's (DSS) Electronic Control Unit (ECU) is incorrectly programmed, which can disable the Pre-Collision System (PCS) and Dynamic Radar Cruise Control (DRCC):
Pre-Collision System (PCS)
Uses radar and other sensors to detect potential collisions with obstacles, and can automatically apply brakes and tighten front seat belts
Dynamic Radar Cruise Control (DRCC)
Uses vehicle-to-vehicle distance control to automatically accelerate or decelerate to maintain a set distance from vehicles ahead