P1326 on Hyundai: How to Diagnose & Fix

The Theta II GDI engine in 2011-2019 Tucson models is susceptible to connecting rod bearing failure caused by manufacturing debris restricting oil flow. This can lead to catastrophic engine seizure, often without warning. Hyundai issued multiple recalls (19V-601, 20V-150) and extended the engine warranty to 15 years/unlimited miles for original owners.

Hyundai recalled certain 2025-2026 Tucson and Santa Fe vehicles under NHTSA campaign 25V549000 because connecting rod bolts in the engine may have been improperly tightened during assembly. Under-torqued rod bolts allow the big-end bearing cap to work loose, which progresses to bearing failure, rod knock, and ultimately a thrown rod that can breach the block. NHTSA's stated consequences are loss of drive power, which raises crash risk, and an oil leak onto hot engine components that raises the risk of an engine compartment fire. The severity of the remedy is the tell: Hyundai is replacing the entire engine rather than inspecting or re-torquing, which indicates the defect cannot be reliably screened for in service. Owner notification letters were mailed October 23, 2025 under Hyundai's internal recall number 281. The campaign names the Tucson and Santa Fe without listing Hybrid or PHEV variants, unlike Hyundai's other Tucson campaigns which name them explicitly — so this affects the conventional 2.5L gasoline powertrain.

Separate from fuel-in-oil dilution, a population of 3.8L Lambda II GDI V6 Palisades burns oil at a high rate — owners report as much as a quart per 500-600 miles with no external leak. Because the engine holds a fixed sump and the oil life monitor does not account for consumption, the level falls below safe pressure between services and starves the connecting rod bearings. The Knock Sensor Detection System then hears the bearing knock signature and sets P1326, flashing the CEL and dropping the vehicle into limp mode at roughly 1,800-2,000 rpm. Teardowns of failed 2020-2022 cars show rod bearings flaked and scored from metal-to-metal contact, with full failures reported between roughly 70,000 and 90,000 miles.

Hyundai's 1.6-liter Gamma GDI engines in 2015-2016 Velosters built May 26, 2014 through July 13, 2016 may have been produced with conditions that cause premature connecting-rod-bearing wear. A worn bearing produces a knocking noise and/or oil-pressure warning, then the rod can seize or punch through the block, stalling the car and leaking oil onto hot surfaces. NHTSA opened PE19-003 into these fires and Hyundai recalled 128,948 vehicles across four models under 20V-746 (Hyundai Recall 198), the Veloster being the largest population. Earlier 2012-2014 Velosters with the same engine family were not recalled but received Service Campaign 966, a Knock Sensor Detection System software update that sets P1326 and forces limp mode when bearing-wear vibration is detected; owners on veloster.org report both sudden rod knock and dealer warranty denials on the KSDS extended coverage.

On the RB-generation Accent with the 1.6L Gamma GDI engine (G4FD), the connecting-rod bearings wear and fracture prematurely, releasing metal debris into the oil. As clearances open up the engine develops a metallic knock/rattle that is loudest when warm and under load, then progresses to a rod knock, loss of oil pressure and eventually seizure or a thrown rod. Owners on Hyundai Forums reported the rattle from as early as 2012 cars with normal maintenance history, and Hyundai later rolled out the Knock Sensor Detection System (KSDS) software (Service Campaign 966, expanded by 982) which monitors the knock sensor for abnormal bearing noise, blinks the MIL and drops the car into Engine Protection Mode before the engine destroys itself. Hyundai deployed KSDS software and an engine warranty extension across several of its GDI engine families, but the Accent is NOT on the published covered-vehicle lists for KSDS Campaign 966/982 or the Hyundai/Kia GDI engine-failure settlement. Do not assume this car is covered - verify your VIN with Hyundai before expecting a free repair.

NHTSA recall 21V-301 covers 95,223 model-year 2019-2021 Kona vehicles equipped with 2.0-liter Nu MPI engines. Inconsistent nitride heat treatment can make a piston oil ring excessively hard, allowing its outer edge to chip and scuff the cylinder bore. Resulting oil consumption and engine damage can cause knocking, reduced power or hesitation, warning lights and, with continued operation, a seized connecting-rod bearing, engine stall or an oil-fed fire.

NHTSA recall 17V-226 (Hyundai recall 162) covers certain model-year 2013-2014 Santa Fe Sport vehicles equipped with 2.0-liter or 2.4-liter gasoline-direct-injection engines. Residual debris from factory machining can restrict oil flow to the main bearings and cause premature bearing wear. A worn connecting-rod bearing can produce cyclic engine knock or illuminate the oil-pressure lamp; if the bearing fails, the vehicle can lose motive power while moving.

NHTSA recall 20V-746 (Hyundai recall 198) covers certain model-year 2012 Santa Fe vehicles equipped with the 2.4-liter Theta II MPI engine. Conditions in the engine can cause premature connecting-rod-bearing wear. Continued operation with a worn bearing can damage the engine and eventually stall the vehicle; in limited cases, a damaged connecting rod can puncture the engine block, release oil onto hot components and increase fire risk.

The Theta II GDI engine (2.4L MPI/GDI and 2.0T) suffers premature connecting-rod bearing wear. NHTSA determined that metal debris left from crankshaft machining, plus uneven crankpin surface roughness, restricts oil flow to the rod bearings, raising bearing temperatures and causing premature wear. A worn bearing produces a metallic, cyclic knocking noise that increases with RPM; if driven further the bearing fails, the engine can seize and stall while in motion, and a fractured rod can puncture the block, letting oil reach hot surfaces and start an engine-compartment fire. This is the defect behind multiple recalls (Campaign 132 / NHTSA 15V-218 for 2011-2012 2.0T/2.4 GDI built at HMMA; Campaign 198 / NHTSA 20V-746 covering Sonata Hybrid and others), a $210M NHTSA civil penalty consent order, and a ~$1.3B class-action settlement covering roughly 3.9M Hyundai/Kia owners.