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Wisconsin · Topic Updated May 24, 2026

Qualifying Defects Under Wisconsin Lemon Law

What kinds of vehicle defects qualify for a Wisconsin Lemon Law refund — the substantial-impairment test under Wis. Stat. § 218.0171(1)(f).

A defect qualifies under the Wisconsin Lemon Law when it constitutes a “nonconformity” that substantially impairs the use, value, or safety of the vehicle under Wis. Stat. § 218.0171(1)(f).

Topics in this section

The substantial-impairment test in Wisconsin

Wis. Stat. § 218.0171(1)(f) defines a “nonconformity” as a defect that “substantially impairs the use, value, or safety” of the vehicle. Three-prong test (use OR value OR safety) — matching most peer states.

No separate serious safety defect category

Wisconsin doesn’t have a separate lower repair-attempt threshold for serious safety defects like Virginia, Georgia, or Washington. All defects use the same four-attempt or 30-day OOS thresholds under § 218.0171(1)(h).

What’s substantial vs. trivial

  • Transmission that shifts hard — qualifies.
  • Engine that stalls — qualifies.
  • Brake-pedal feel that varies — qualifies.
  • HVAC defroster system failure — qualifies (critical in Wisconsin winter).
  • Power-window switch — typically doesn’t qualify alone.

What’s NOT a qualifying defect

  • Damage from accidents.
  • Damage from unauthorized modifications.
  • Normal wear.
  • Neglect or misuse.
  • Cosmetic flaws.
  • Defects caused by the consumer.

How qualifying defects interact with repair-attempt counts

A qualifying defect alone isn’t enough — the consumer must meet § 218.0171(1)(h) thresholds: four attempts for the same nonconformity, OR 30 cumulative calendar days OOS, within the 1-year Rights Period.

Great Lakes / cold-weather factors

Wisconsin’s cold climate and aggressive winter road salt stress vehicles:

  • Underbody corrosion — winter road salt aggressive on brake lines, fuel lines, exhaust systems.
  • HVAC defroster — critical 6 months per year.
  • Cold-start systems — sub-zero Wisconsin winters stress starters, batteries, fuel systems.
  • Tire wear — winter / summer tire cycling.
  • EV cold-weather range degradation — Wisconsin winters significantly reduce EV range.

Document weather conditions when symptoms manifest.

What court / BBB Auto Line considers

  • Clean documentation.
  • Consistent symptoms across visits.
  • Defect persistence after the final repair opportunity.
  • Aligned with documented TSBs or recalls.
  • For double-damages exposure: manufacturer’s response to written election within 30 days.

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