Any one of the three will trigger the consumer's rights under the lemon law.
Manufacturers try to impose their own definitions of impairment.
Courts generally don't accept this argument. In a lawsuit against Ford Motor Co., an owner tearfully recounted the time when she was pregnant and her car stalled on the railroad tracks. Clearly this impaired the vehicle's safety for her. It also impaired her use. In addition, because most consumers couldn't, in good conscience, think of selling such a car without disclosing its problems to the next owner, the vehicle's value was substantially reduced.