Keep your LML Duramax emissions system running clean and efficient with OEM-quality replacement components. This category features Diesel Particulate Filters (DPF), Diesel Oxidation Catalysts (DOC), Selective Catalytic Reduction (SCR) units, DEF system parts (pumps, heaters, sensors, tanks), emissions sensors (NOx, EGT, differential pressure), and installation gaskets—everything needed to maintain compliance and avoid expensive dealership repairs. Whether you're replacing a clogged DPF, failed DEF pump, or faulty sensor, NorCal stocks trusted aftermarket and OEM components backed by warranties and ready to ship.
The 2011–2016 GM 6.6L LML Duramax introduced a sophisticated four-stage exhaust aftertreatment system designed to meet stringent EPA emissions standards while delivering impressive performance—397 horsepower and 765 lb-ft of torque straight from the factory. This generation marked a significant evolution in diesel emissions technology with the addition of Selective Catalytic Reduction (SCR) and Diesel Exhaust Fluid (DEF) injection, achieving a remarkable 60% reduction in NOx emissions over previous Duramax engines.
The LML Duramax aftertreatment system works as an integrated network of emissions components that treat exhaust gases before they exit the tailpipe. Starting from the turbocharger, the system flows through the Diesel Oxidation Catalyst (DOC), which converts harmful carbon monoxide and hydrocarbons into carbon dioxide and water while oxidizing NOx into nitrogen dioxide for further processing. Exhaust then passes through the Selective Catalytic Reduction (SCR) system, where DEF—a 32% urea solution—is injected to neutralize nitrogen oxides. Finally, the Diesel Particulate Filter (DPF) captures soot and particulate matter, achieving up to 90% filtration efficiency and burning off collected particles during regeneration cycles when exhaust temperatures exceed 1,022°F.
This category features OEM and high-quality aftermarket replacement parts essential for maintaining your LML Duramax emissions system at peak efficiency:
Diesel Particulate Filters (DPF) serve as the primary soot collection device and are among the most commonly replaced aftertreatment components. When DPFs become clogged or damaged, they restrict exhaust flow and trigger frequent regeneration cycles, negatively impacting fuel economy and performance.
Diesel Oxidation Catalysts (DOC) are critical first-stage components that must reach operating temperatures between 250°F and 750°F to initiate proper aftertreatment function. A failing DOC will prevent effective soot burn-off and reduce overall system efficiency.
SCR Catalysts work in conjunction with DEF injection to reduce nitrogen oxide emissions to near-zero levels. These components require replacement when they become contaminated or lose catalytic efficiency.
DEF System Components include pumps, heaters, injectors, and tanks that work together to deliver precise amounts of diesel exhaust fluid into the exhaust stream. The DEF pump supplies fluid from the tank to the injector, while heaters prevent crystallization in cold temperatures—essential since DEF freezes at -11°F. Common replacement parts include the DEF pump assembly (OE# 22902634), DEF heaters (OE# 23379346), and tank level sensors.
Emissions Sensors monitor system performance throughout the aftertreatment process. NOx sensors positioned upstream and downstream of the SCR measure nitrogen oxide levels before and after DEF treatment, enabling the ECM to calculate precise dosing requirements. Temperature sensors placed before the DOC, between the DOC and DPF, and after the SCR regulate regeneration cycles by monitoring exhaust temperatures. Pressure differential sensors across the DPF detect blockages and determine when regeneration or cleaning is necessary.
Gaskets and Clamps ensure exhaust heat and pressure remain sealed within the system, preventing leaks that compromise aftertreatment efficiency. High-quality replacement gaskets designed to OEM specifications are essential for proper installation of DPFs, DOCs, and SCR components.
The interconnected nature of the LML emissions system means that failure in one component often cascades to affect others. A faulty DEF heater, for example, can damage the pump and NOx sensors by preventing urea injection during cold operation, which subsequently affects fuel-air mixture composition and may accelerate DPF clogging. Increased DEF consumption, reduced fuel economy, rough idling, and check engine lights are common warning signs of aftertreatment system issues.
NorCal Diesel Performance stocks OEM-quality aftertreatment components for your 2011–2016 Chevy Silverado and GMC Sierra 2500HD/3500HD equipped with the 6.6L LML Duramax. Whether you need a complete DPF replacement, DEF system repair parts, emissions sensors, or installation hardware, our inventory includes direct-fit solutions backed by manufacturer warranties. Keep your diesel running clean, efficient, and trouble-free with genuine replacement aftertreatment parts designed specifically for the LML platform.
