When your 2023 Chevrolet Tahoe displays the P0305 code, the engine control module has detected repeated misfires in cylinder 5. The 2023 Tahoe offers V8 engines (5.3L and 6.2L) and the 3.0L Duramax inline-six diesel—all with at least six cylinders, making P0305 a valid code on all configurations.
2023 Tahoe Powertrain Options
The 2023 Tahoe continues with the 5.3L V8 (355 hp) as the base engine, the 6.2L V8 (420 hp) as an upgrade, and the 3.0L Duramax I-6 diesel (277 hp) option. V8 models feature Dynamic Fuel Management (DFM) cylinder deactivation technology.
Cylinder 5 Location
On GM V8 engines, cylinder 5 is located at the front of the driver side bank. GM's cylinder numbering places odd cylinders (1,3,5,7) on the driver side and even cylinders (2,4,6,8) on the passenger side. The diesel's inline-six has cylinder 5 toward the rear of the engine.
Common Causes
DFM lifter concerns continue on some GM V8 engines, with lifter failures causing misfires in specific cylinders. Spark plug wear occurs over time, particularly with towing or heavy use. Ignition coil failure can happen individually. Carbon buildup from direct injection affects valve sealing over time. Fuel system issues including injector problems can cause lean misfires.
Diagnostic Approach
Read all diagnostic codes including DFM-related codes. Inspect cylinder 5's spark plug and ignition coil. Check oil condition and maintenance history—DFM requires proper oil. Review GM TSBs for any known issues with the 2023 model year. If lifter concerns exist, valve train inspection may be warranted.