Chevrolet vehicles generally pass California smog without issue, but V8 models equipped with Active Fuel Management (AFM) cylinder deactivation are at elevated risk of misfire codes that cause smog failure — especially if the vehicle has high mileage or oil consumption.
- Active Fuel Management (AFM) on 5.3L and 6.2L V8 engines (Silverado 1500, Tahoe, Suburban, Camaro SS) causes lifter failures that generate misfire codes P0300-P0308 — a guaranteed smog fail
- AFM lifter issues typically emerge between 80,000 and 150,000 miles; oil consumption is a leading indicator
- 2003-2009 Silverado/Tahoe with 5.3L: catalytic converter degradation on high-mileage examples is common after AFM lifter events
- Equinox 2.4L (2010-2017): oil consumption issues can cause fouled O2 sensors and cat converter contamination
- Silverado 2500HD/3500HD Duramax 6.6L diesel: intact DPF, EGR, and DEF required — any delete or aftermarket tuner that alters emissions = automatic fail
- Colorado and Canyon 2.8L Duramax diesel: same DPF/EGR requirement as HD trucks
Per BAR inspection data and GM AFM technical service bulletins.