The P0303 diagnostic code on your 2021 Toyota Highlander indicates that the engine control module has detected cylinder 3 misfires exceeding acceptable thresholds. This three-row SUV features capable powertrains.
2021 Highlander Powertrain Options
The 2021 Toyota Highlander offered a 3.5L V6 producing 295 horsepower in standard models, plus a hybrid variant combining a 2.5L four-cylinder with electric motors for 243 combined horsepower.
3.5L V6 Configuration
In Toyota's V6, cylinder 3 is located on one bank. Bank-specific fuel trim imbalances should be considered during diagnosis. The V6 uses D-4S dual injection technology.
Hybrid System
The Highlander Hybrid uses a 2.5L four-cylinder instead of the V6. Misfires affect the combustion engine specifically, with electric motors providing supplemental power.
Family SUV Reliability
The Highlander serves as primary family transportation for many owners. Reliable operation is essential. Address misfires promptly.
Toyota Quality
The Highlander's reliability makes misfires relatively uncommon. Proper diagnosis identifies the root cause for effective repair.