2019 GMC Sierra 3500HD Problems: 19 Issues Every Owner Should Know
2019 model year · 2,875+ owner reports · Updated May 2026
According to Au7o's analysis of 2,875+ owner reports, the 2019 GMC Sierra 3500HD has 19 documented known issues, with 7 rated critical. The most serious are CP4.2 High-Pressure Fuel Pump Catastrophic Failure ($10,000-$18,000 repair), DPF (Diesel Particulate Filter) Clogging and Regeneration Failure ($300-$3,500 repair), Turbocharger VGT Vane Sticking and Boost Control Failure (Duramax LML/L5P) ($200-$3,500 repair), Trailer brake controller / integrated trailer brake module malfunction ($80-$900 repair), Allison 1000 Transmission Control Module and Sensor Failures ($500-$3,500 repair), Diesel Injector Failure Causing White Smoke and Rough Running ($600-$5,000 repair) and Rear Leaf Spring Breakage Under Heavy Loads ($400-$1,500 repair). The most commonly reported issue is CP4.2 High-Pressure Fuel Pump Catastrophic Failure with 440 owner reports. Across all issues, repair costs range from $80 to $18,000. DIY maintenance guides at .