The P0303 diagnostic code on your 2023 Toyota Sienna indicates that the engine control module has detected cylinder 3 misfires exceeding acceptable thresholds. This hybrid minivan requires proper diagnostic attention.
2023 Sienna Powertrain
The 2023 Toyota Sienna continues as a hybrid-only model with the 2.5L Dynamic Force four-cylinder and electric motors producing 245 combined horsepower and excellent fuel economy.
D-4S Technology
The 2.5L uses dual injection combining direct and port injection. Port injection sprays fuel over intake valves, reducing carbon buildup while direct injection maximizes efficiency.
Four-Cylinder Impact
Each cylinder contributes 25% of combustion power. Cylinder 3 misfires create rough running that affects the smooth operation expected in a family minivan.
Hybrid Integration
The combustion engine works with electric motors, but misfires still affect overall operation and efficiency. The hybrid cannot fully compensate for engine problems.
Warranty Coverage
Your 2023 Sienna is protected by Toyota's warranty. Misfire repairs should be covered. Contact your dealer.