A P0303 code in your 2020 Nissan Pathfinder indicates the engine control module has detected persistent misfires at cylinder 3. This three-row SUV uses Nissan's proven 3.5L VQ35DD V6 engine, producing 284 horsepower. Understanding the V6 layout and common failure points helps ensure accurate diagnosis of this family-oriented vehicle.
Cylinder 3 Location in the 3.5L V6
The VQ35DD is a V6 engine with cylinders numbered 1-3 on one bank and 4-6 on the other. Cylinder 3 is the rearmost cylinder on the front (radiator side) bank. This positioning provides relatively straightforward access for spark plug and coil service from above.
Direct Injection Technology
The VQ35DD features direct fuel injection, enhancing power and efficiency. However, direct injection means fuel doesn't wash across intake valves, allowing carbon deposits to accumulate over time. These deposits can restrict airflow to cylinder 3 and contribute to misfires.
Common P0303 Causes at Four to Five Years
At this age, several wear-related issues may cause cylinder 3 misfires. Spark plug degradation affects ignition quality. Ignition coil failures occur from heat cycling. Fuel injector clogging or electrical issues affect fuel delivery. Carbon buildup restricts intake airflow. Intake manifold gasket leaks create vacuum imbalances.
VQ35 Engine Family Reliability
Nissan's VQ series V6 engines have an excellent reputation for reliability and have won numerous industry awards. Proper maintenance including timely spark plug replacement and quality oil helps ensure continued dependability.