A P0302 code on your 2023 Chevrolet Suburban signals that the engine control module has detected misfires in cylinder 2. The twelfth-generation Suburban offers three engine choices: the 5.3L V8 (L84), 6.2L V8 (L87), and the 3.0L Duramax turbo-diesel inline-6 (LM2). Each powertrain requires different diagnostic approaches for cylinder 2 misfire resolution.
Understanding Engine Options
The V8 engines use Dynamic Fuel Management (DFM), an evolution of AFM that can deactivate any combination of cylinders. Cylinder 2 on the V8s is on the passenger side and participates in DFM operation. The 3.0L Duramax is an inline-6 configuration where cylinder 2 is second from front. Diesel misfires have fundamentally different causes than gasoline engine misfires.
V8 Misfire Causes
DFM lifter issues remain a potential cause, though the 2023 models use updated lifter designs. Ignition coil and spark plug failures are common on any gasoline V8. Direct injection carbon buildup can affect intake valve sealing on cylinder 2. Fuel injector problems and low fuel pressure also cause misfires.
Duramax Diesel Causes
The 3.0L Duramax triggers P0302 due to fuel injector failure, low rail pressure, glow plug problems, or compression loss. Diesel engines don't use spark plugs, so ignition-related causes don't apply. Injector coding errors after service can cause cylinder-specific misfires.
Symptoms and Detection
Both engine families display rough idle and hesitation. V8 misfires may be more noticeable when DFM is active. Diesel misfires often produce different exhaust characteristics including smoke. The check engine light illuminates in both cases, with severe misfires causing a flashing light.
Repair Strategies
V8 repairs begin with ignition component inspection and replacement. DFM lifter service may be required if noise or AFM codes are present. Duramax repairs focus on fuel system integrity, injector replacement, and compression verification. Given the 2023 model year, warranty coverage should apply to most repairs.