The P0302 code on your 2021 Toyota Highlander indicates a cylinder 2 misfire detected by the engine control module. The Highlander's 3.5L 2GR-FKS V6 engine is generally reliable, but understanding the misfire causes specific to this engine helps with effective diagnosis.
V6 Engine Cylinder Layout
The Highlander's V6 has cylinders numbered 1-3 on the front bank and 4-6 on the rear bank. Cylinder 2 is the center cylinder on the front bank, making it relatively accessible for diagnosis. This transverse-mounted engine positions cylinder 2 toward the center of the engine bay.
Common P0302 Causes on the V6
Typical cylinder 2 misfire causes include ignition coil failure (individual coil-on-plug design), spark plug wear or damage, fuel injector issues, intake manifold vacuum leak, and less commonly, mechanical issues like valve or compression problems.
Diagnostic Procedure
Access the front bank coils by removing the engine cover. Swap the cylinder 2 coil with cylinder 1 or 3 and clear codes. Test drive to see if the misfire code moves with the coil. Similarly test the spark plug if the coil swap doesn't identify the issue. The V6's individual coil design makes isolation testing straightforward.
V6-Specific Considerations
The 2GR-FKS uses both port and direct injection (D-4S), helping reduce carbon buildup concerns. However, if other components check out, intake valve inspection may be warranted. Check for TSBs related to V6 misfire issues.