2021 GMC Yukon XL

Reliability tier: verified - see /disclosure/

Engine: 3.0L Duramax LM2 (Duramax, 3.0L)

LM2 3.0L Duramax I6 (DOHC): 277 hp @3,750 / 460 lb-ft @1,500; aluminum block/head, Opel-derived I6 engineered in Turin, built at Flint; Hydra-Matic 10L80 10-speed. In-tank lift pump feeds the high-pressure pump.

Applicable failure modes (8)

• Coolant flow control valve failure (active thermal management)
• DEF system faults: tank heater, pump/quality (speed-limited derate)
• DPF regeneration and ash-loading faults
• EGR system failures: valve, cooler, wiring (derate-prone)
• Extended crank / long-crank no-start (air intrusion, check valve, cam wheel)
• NOx sensor / SCR efficiency codes
• Transmission control valve failure and rear-wheel lock-up (recall 24V-797)
• Turbo and boost-path faults (coolant line, charge air)

Applicable parts (3)

• DEF refill - fresh API-certified fluid (service item, all 3.0L Duramax)
• DPF cleaning service (professional bake-and-blow, off-truck)
• 3.0L Duramax Drop-In Fuel System / Lift Pump (FASS, 2019-2026 GM 3.0 LM2/LZ0)

Platform recipes (4)

• Coolant flow control valve job for the 3.0L Duramax (mode fm-lm2-coolant-control-valve): high fan, fluctuating temp, P1098, 'Engine Power Reduced'
• DEF tank-side service for the 3.0L Duramax (mode fm-lm2-def-system): the 'Exhaust Fluid System' warnings walk up a derate ladder to 5 mph
• EGR cooler / valve job for the 3.0L Duramax (mode fm-lm2-egr-system): rarely named in NHTSA complaints (8 of 1,190) but forum-documented - recurring 'Service Emission System' with the 65-mph derate
• Fuel filter service with a proper prime for the 3.0L Duramax (mode fm-lm2-long-crank): the #1 self-inflicted long-crank is air trapped after a filter change - seat the housing fully, cycle key-on and let the pump prime before cranking

Recalls that include this truck (1)

• 24V-797 (October 24, 2024) - POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE: General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL...

Matched by the model and model year NHTSA lists for each recall - a recall often covers only part of a year's production, so read its text for the build dates and versions it names. Whether a recall is still open on your VIN is not known here; check nhtsa.gov/recalls. All recalls, investigations and bulletins for this engine: /recalls/duramax-lm2-lz0/

Reference for this truck