P0420 on Honda

The 8th generation Accord V6 (3.5L J35Z2) with Variable Cylinder Management (VCM) deactivates 3 cylinders at highway speeds, causing excessive oil consumption (1 quart per 1,000-1,500 miles), misfires, and accelerated engine vibration that damages engine mounts. When VCM deactivates cylinders, insufficient ring pressure allows oil to bypass rings into combustion chamber. The class action lawsuit (Rodriguez v. American Honda, 2013) covered 1.87 million vehicles. Honda settled in 2016 providing extended warranty for engine repairs related to VCM-caused misfires and oil consumption. Many owners in the Drive Accord community disable VCM immediately upon purchase.

The 11th generation Civic (2022+) reports two prominent issues: (1) Excessive oil consumption on 1.5T engines consuming 0.5-1 quart per 1,000 miles, particularly in the first 10,000-20,000 miles before rings seat. Honda issued TSB 22-078 acknowledging consumption up to 1 quart per 3,000 miles as "within specification" but owners consistently report higher levels. (2) Honda Sensing phantom braking and false frontal collision warnings on the 2022+ system. NHTSA received over 600 complaints about unexpected autonomous emergency braking (AEB) activation on 2022-2024 Civics. NHTSA opened a preliminary investigation PE22-029.

Gasoline mixes with engine oil in the 1.5L turbocharged engine, causing the oil level to rise above the full mark. The issue is most prevalent in cold climates where short trips don't allow the engine to reach full operating temperature. Unburned fuel bypasses the piston rings and enters the crankcase, diluting the oil and reducing its lubricating properties.

The 2010-2012 Honda Crosstour with J35Z2 V6 engine and VCM (Variable Cylinder Management) experiences severe oil consumption, often consuming 1 quart every 1,000-1,500 miles. The VCM system deactivates cylinders for fuel economy, but this causes improper ring oiling, damaging piston rings and cylinder walls. Symptoms include excessive oil consumption, misfires, fouled spark plugs, and engine damage. The 2013+ Crosstour uses the J35Y1 engine which fixed VCM issues. Solutions: VCM Muzzler ($170) to disable VCM, or frequent oil top-offs. Engine rebuild/replacement: $4,000-8,000.

K24A engine develops abnormal oil consumption after 100k-150k miles. Stuck oil control rings from infrequent changes or wrong viscosity oil. Mobil 1 synthetic 5W-20 is Element Owners Club community standard. Change oil every 5,000 miles (not 7,500) to prevent consumption. Avoid cheap/wrong viscosity oil. Element owners consistently report longevity when using quality oil. No permanent fix for late-stage consumption - keep oil topped off.

The 2000-2006 Honda Insight (first generation) experiences premature catalytic converter failures. The lean-burn engine runs very lean, putting extra stress on the catalytic converter. Symptoms include check engine light with P0420/P0430 codes, rattling noise from exhaust, reduced power, and failed emissions test. OEM Honda catalytic converter: $1,200-2,000. Aftermarket: $400-800.

Variable Cylinder Management (VCM) deactivates 3 rear cylinders during light load, but insufficient pressure allows oil to bypass piston rings into combustion chamber. Causes excessive oil consumption (1 quart per 1,000 miles), fouled spark plugs, catalytic converter damage, and premature piston ring wear. Honda settled class-action lawsuit covering 1.6-1.87 million vehicles.

The 3.2L V6 used in the first-generation Passport is known to develop exhaust leaks from broken manifold studs or warped manifold sealing surfaces as the vehicle ages. Owners commonly describe a ticking noise on cold start, exhaust smell, and occasional failed emissions testing. Heat cycling and corrosion are the usual causes, and the repair can become labor-intensive if studs snap flush in the cylinder head.

Variable Cylinder Management (VCM) causes excessive oil consumption (1 quart every 1,000-1,500 miles), engine misfires, and fouled spark plugs. The reciprocating effect creates vacuum that pulls oil past piston rings. Leads to premature failure of spark plugs, catalytic converters, engine mounts, and cylinder walls. 2013 class action lawsuit identified 1.6 million affected vehicles.

Variable Cylinder Management (VCM) deactivates 3 cylinders during light-load driving to improve fuel economy. When inactive cylinders reactivate, vacuum pulls oil past piston rings into the combustion chamber, causing excessive oil consumption (1 quart per 1,000-1,500 miles vs. normal 1 quart per 3,000-5,000). Oil burning causes spark plug fouling, misfires, rough idle, and accelerated catalytic converter wear. 2013 class action lawsuit identified 1.6 million affected Honda vehicles including 2006-2013 Ridgelines.