If your 2021 Toyota Highlander displays a P0305 code, diagnosis depends on your powertrain configuration. The Highlander is available with either the 3.5L V6 or hybrid (four-cylinder based). P0305 only applies to V6 models.
V6 Highlander: Understanding P0305
In the 3.5L V6 Highlander, cylinder 5 is located on the rear of the left bank. The V6 uses individual coil-on-plug ignition for precise misfire detection.
Hybrid Highlander: Anomalous Code
If your 2021 Highlander is a Hybrid, it uses a 2.5L four-cylinder engine. P0305 refers to a non-existent cylinder, indicating a diagnostic anomaly.
Diagnostic Approach
First, confirm your powertrain type. For V6: access cylinder 5 ignition coil and inspect spark plug. For Hybrid: investigate diagnostic system anomaly.