The 2022 Mercedes-Benz GLC X253 generation is equipped with the M264 2.0-liter turbocharged 4-cylinder engine in GLC 300 models, which represents the vast majority of North American sales. A P0305 code indicating cylinder 5 misfire presents a diagnostic puzzle since this engine only contains four cylinders.
The P0305 Code Paradox
Standard OBD-II code P0305 indicates "Cylinder 5 Misfire Detected," but the M264 engine in your 2022 GLC has cylinders numbered only 1 through 4 in its inline-four configuration. This code appearing suggests a diagnostic system anomaly requiring investigation beyond typical misfire troubleshooting.
2022 GLC 300 Engine Details
The M264 engine produces 255 horsepower from 2.0 liters of displacement using turbocharging and direct injection technology. The 4-cylinder design utilizes a 1-3-4-2 firing order, and the engine management system is calibrated specifically for four-cylinder operation.
Investigating the Anomalous Code
Proper diagnosis requires Mercedes-Benz XENTRY equipment to analyze actual misfire counter data for each of the four physical cylinders. The technician should determine whether real misfires are occurring on cylinders 1-4 while being reported incorrectly, or if this is purely a software/communication error.
Potential System Issues
Erroneous cylinder 5 codes on 4-cylinder vehicles may indicate ECU software corruption requiring reflash, control module communication errors on the CAN bus, aftermarket device interference with diagnostic systems, or in rare cases, a failing engine control module.