A week ago, the master warning light, check engine light, and hybrid system warning light came on when I started the car. These lights reset themselves after the second engine restart. Last Saturday, these same lights came on again and stayed on, even during the drive to Toyota of Killeen. Unfortunately, the Prius tech had the day off so Monday was the earliest day my car could be fixed. Picked up my car Monday afternoon. The code was P3191. Parts replaced was the engine control computer ($1,092.00) and a relay ($70.26). The computer was replaced under the hybrid warranty; the relay under the extended warranty. My cost was zero dollars. Mileage on the car was 42,302.