Complaint counts get quoted as a reliability score. They are not one — a count says how much trouble a model generated, and nothing about what kind.
The useful version is the shape. For 714 models with at least fifty complaints on record, we worked out which component category holds the largest share.
| Dominant component | Models where it leads | Share of models |
|---|---|---|
| Electrical system | 149 | 21% |
| Engine | 94 | 13% |
| Air bags | 90 | 13% |
| Power train | 86 | 12% |
| Service brakes | 69 | 10% |
| Engine and cooling | 61 | 9% |
| Steering | 32 | 4% |
| Structure | 20 | 3% |
Electrical faults lead on one model in five — more than engine and powertrain combined at the top of their respective lists.
Some models concentrate almost everything
The average model spreads its complaints across several systems. A minority do not.
| Model | Dominant fault | Share of that model's complaints | Complaints |
|---|---|---|---|
| BMW Z4 | Steering | 73% | 1,325 |
| Lexus RX | Power train | 73% | 93 |
| Subaru SVX | Power train | 72% | 346 |
| Daewoo Leganza | Engine and cooling | 72% | 565 |
| Scion FR-S | Engine | 66% | 228 |
The Z4 is the case worth studying. 1,325 complaints is a substantial volume — this is not a small sample producing a fluke — and nearly three-quarters of them name the steering.
That is not a car with a reliability problem. It is a car with one specific problem, and those are different things to buy.
Concentrated is easier to live with than diffuse
This runs against instinct. A model where 73% of complaints point at one system sounds worse than one where they spread evenly.
In practice it is the opposite, because a concentrated fault is actionable. You know what to inspect before buying, what symptoms to test for, what the repair costs, and whether it has already been done. The risk is quantifiable.
A model with three hundred complaints spread across six systems gives you nothing to check. Any of it might fail, none of it is predictable, and no inspection covers everything.
So the question to ask about a model is not how many complaints it has, but whether they point somewhere.
Why electrical leads the table
Electrical faults dominate more models than anything else, and the reason is arithmetic rather than quality.
Every function that used to be mechanical is now electrical. Windows, mirrors, locks, seats, throttle, steering assistance, climate, instruments. The category has grown to include most of the car, so it collects complaints from everywhere.
It is also the category we found reports slowest — 165 days between incident and filing, against 118 for steering — and the one most likely to end in a fire, at 9.3% of its complaints.
Using this before you buy
Find the dominant category for the specific model and year, then build the inspection around it. On a Z4, that means a proper steering assessment rather than a general once-over.
And check whether the known fault has already been addressed on that particular car — many dominant faults eventually produce a recall, and the repair is free but only happens if somebody books it.
A free VIN check shows what is still open on the vehicle in front of you.
Frequently asked questions
Which component generates the most complaints overall?
The electrical system. Across 714 models with at least 50 complaints on record, electrical faults are the single largest category for 149 of them — 21%. Engine follows at 13% of models, airbags at 13% and powertrain at 12%.
What does a concentrated fault profile mean?
That a model has one dominant weakness rather than general unreliability. The BMW Z4 concentrates 73% of its 1,325 complaints into steering, and the Subaru SVX puts 72% into the powertrain. A concentrated profile is easier to plan for — you know what to inspect and what to budget for.
Is a spread-out complaint profile better or worse?
Neither by itself, but it is harder to act on. A model whose complaints spread evenly across six systems gives you no single thing to check, whereas a model with one dominant fault tells you exactly where to look and what a repair will cost.
How do I find the weak point of a specific model?
Look at which component category holds the largest share of its complaints rather than the raw total. A model with 300 complaints spread evenly is a different proposition from one with 300 complaints where 200 are the transmission — the second is a known, priceable risk.
Denis Kataev is a serial solopreneur and the founder of ForCar. With 15+ years in software engineering and 10 years in SEO, he builds data-driven products end to end — backed by a sharp eye for design. At ForCar he mines proprietary vehicle datasets, turning raw numbers into buying advice you can actually trust.
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