2019 GMC Sierra 2500HD Problems: 6 Known Issues

On the 2011-2020 GMC Sierra 2500HD, the Bosch CP4.2 high-pressure fuel injection pump used on the 2011-2016 LML and 2017-2020 L5P Duramax diesel engines is prone to catastrophic failure that destroys the entire fuel injection system. Unlike its predecessor the CP3, the CP4.2 lacks a roller element and relies solely on fuel for lubrication. When metal fatigue occurs, the pump shatters and sends metal debris throughout the entire high-pressure fuel system — contaminating all six injectors, the fuel rails, return lines, and feed lines. Total repair cost runs $8,000-18,000. A class action lawsuit was filed against GM. The same pump also fails in Ford 6.7 Power Stroke and Ram 6.7 Cummins of the same era.

On the 2014-2020 GMC Sierra 2500HD, the 6.0L L96 V8 gasoline engine in Sierra 2500HD (non-diesel) suffers from Active Fuel Management (AFM) lifter failures similar to the 5.3L in Sierra 1500 — though less frequently due to the higher displacement. More commonly, 6.0L engines exhibit excessive oil consumption (1 qt per 1,000-3,000 miles) from worn valve stem seals and piston rings, particularly between 100,000-150,000 miles. The L96 is a high-output truck engine subjected to heavy towing and payload, which accelerates wear on AFM components.

On the 2011-2025 GMC Sierra 2500HD, the Allison 1000 (gas) and Allison 2000 (diesel) 6-speed automatic transmissions used in Sierra 2500HD/3500HD are widely regarded as extremely durable, but the Transmission Control Module (TCM) and solenoid pack do develop faults. Common issues include harsh 1-2 shifts, transmission sticking in one gear, slip codes, and the truck going into limp mode (3rd gear only). The Allison's proprietary Transynd fluid is critical — using non-approved fluid is the leading cause of premature solenoid wear. TCM software updates from GM address most calibration-related shift complaints.

On the 2011-2019 GMC Sierra 2500HD, nHTSA campaign 23V047000, opened February 2023, covers Sierra 2500HD diesel trucks in which the rear fuel tank can collapse inward under vacuum because the tank does not vent properly as fuel is drawn out. A collapsed tank stops the transfer pump from moving fuel forward, so the truck can run out of usable fuel while the gauge still shows fuel aboard - and stall in traffic. Related to this same family of complaints, GM had earlier recalled 2011-2012 diesel trucks under 13V615000 for a fuel transfer pump that malfunctions and causes inaccurate fuel gauge readings on the same dual-tank arrangement.

On the 2015-2019 GMC Sierra 2500HD, the side-curtain (roof-rail) air bag inflators fitted to GMT900-era and 2015-2019 Sierra 2500HD cabs can have the inflator end cap detach during deployment, releasing compressed gas into the headliner and propelling the cap and headliner components into the occupant compartment. GM has issued a repeating series of NHTSA recalls covering this defect as the affected production population has been refined: 20V736000 and 21V504000 for 2015-era trucks, then 24V756000, 25V432000, 26V166000 and 26V325000 reaching 2018-2019 Sierra 2500HD Crew Cabs. Because a defective inflator can injure the very occupant the bag is meant to protect, NHTSA classes this as a serious safety defect rather than a nuisance.

On the 2011-2023 GMC Sierra 2500HD, sierra 2500HD 4WD trucks use a front axle disconnect system with an electronic actuator and Integrated Wheel End (IWE) hubs. The actuator motor and position sensor commonly fail between 80,000-120,000 miles, causing the 4WD system to not engage, to partially engage (binding and vibration), or to throw a 4WD Service warning. Heavy-duty truck use — particularly towing and off-road — accelerates actuator wear. The IWE hubs (vacuum-operated on some variants, electric on others) also fail, causing a grinding or clicking noise from the front axle in 2WD mode when the hub disengages incompletely.