The 2022 Acura RDX is powered exclusively by a 2.0-liter turbocharged 4-cylinder engine (K20C2) producing 272 horsepower across all trim levels. When a P0305 diagnostic trouble code appears indicating a cylinder 5 misfire, this represents an anomalous diagnostic situation requiring specialized investigation.
Understanding the P0305 Anomaly
The P0305 code translates to "Cylinder 5 Misfire Detected" in standard OBD-II terminology. However, the RDX's turbocharged 4-cylinder engine contains only cylinders numbered 1 through 4. The appearance of this code indicates a diagnostic system irregularity.
RDX Engine History
Previous RDX generations (2013-2018) offered a 3.5L V6 where cylinder 5 was legitimate. The 2019+ redesign switched to a turbocharged 4-cylinder exclusively. P0305 is now an anomalous code on current RDX models.
Diagnostic Protocol
When encountering P0305 on your 4-cylinder RDX, a qualified technician should use Honda/Acura HDS diagnostics to verify actual misfire counter data for cylinders 1-4. Software updates and communication errors should be investigated.
Possible Causes
This anomalous code may result from ECU software requiring updates, control module communication errors, or aftermarket device interference.