GarageCalc What the data says
Engine accounts for about 78% of this year's BMW M340i complaints. That is a strong concentration, the kind that usually points to a specific known issue rather than general wear.
The 2020 model year contributes 18 complaints (67%). No single model year dominates, so this looks like a line-wide pattern rather than one bad year.
Not enough 2025 complaints to compute a year-over-year trend (8 in the same window last year). Year-over-year movement is the most useful signal here: a model's sales are roughly stable from one year to the next, so a sharp rise means the per-vehicle complaint rate genuinely moved, not just that the model is popular.
How to read this
Raw complaint totals track how many BMW M340is are on the road as much as they track quality, so a high count on a best-seller is partly a volume story. Complaints are also self-reported: they capture what owners chose to file, not a controlled survey. Use these numbers to know where to look during a pre-purchase inspection and which recalls to check, not as a verdict on their own. Compare any car instantly in the Car Complaint Checker, or read the full 2026 study for the market-wide picture and methodology.
Frequently asked questions
Is the BMW M340i reliable?
Complaint counts alone cannot answer that, because they track how many are on the road as much as build quality. What the 2026 data shows: 27 NHTSA complaints so far (rank 251 of 765 models), too few 2025 complaints for a trend, with engine the most-cited area. Treat it as a starting point and cross-check recalls and a pre-purchase inspection for the specific vehicle.
What is the most common BMW M340i complaint?
Engine: 21 of the 27 complaints filed in 2026 cite it (about 78%). That is a strong concentration, the kind that usually points to a specific known issue rather than general wear.
Which BMW M340i model year has the most complaints?
The 2020 model year, with 18 of this year's 27 complaints (about 67%). No single model year dominates, so this looks like a line-wide pattern rather than one bad year.
Source: NHTSA Office of Defects Investigation complaint database, complaints received 2026-01-01..2026-08-24, compared with 2025-01-01..2025-08-24 (same window). Counted once per complaint ID, vehicles only. Aggregated data is available under CC BY 4.0 with a link to GarageCalc.