Yes, a used car dealership can sell a car with a check engine code, but there are some important points to consider:

Legal Requirements: Laws and regulations regarding the sale of used cars vary by country and state. In many places, there might not be explicit laws prohibiting the sale of a car with a check engine code. However, deceptive practices may be illegal, so the dealership should be transparent about the condition of the vehicle.

As-Is Disclaimer: Dealerships often sell used cars "as-is" or with a limited warranty. This means the buyer accepts the car's condition at the time of purchase, including any check engine codes or other issues. The dealership should clearly communicate the car's status to the buyer before completing the sale.

Vehicle Inspection: Some dealerships may inspect and repair their used cars before selling them, while others might sell them in their current condition. It's essential for buyers to request a pre-purchase inspection, especially if the check engine light is on.

Negotiation: Buyers have the right to negotiate the price based on the condition of the vehicle. If the car has a check engine code or known issues, the buyer can use that as a bargaining point to lower the price.

Full Disclosure: Ethical dealerships should be honest and upfront about any known problems, including check engine codes. This builds trust with customers and helps them make informed decisions.

Buyer's Responsibility: Once the car is sold, the responsibility to fix any issues, including the check engine code, falls on the buyer, especially if the vehicle was sold "as-is."

Customer Protections: Some areas have lemon laws or consumer protection regulations that may apply to used car sales. These laws can vary widely, so buyers should familiarize themselves with the local laws to understand their rights.

Dealer Reputation: Selling a car with a check engine code might harm the dealership's reputation if customers discover undisclosed issues after the purchase. Building a good reputation for fair dealing is essential for any business.

Preventative Measures: Some dealerships may invest in diagnostic tools and repair services to fix issues before selling a used car, ensuring better customer satisfaction and minimizing potential problems.

In summary, while a used car dealership can sell a car with a check engine code, they should be transparent about the car's condition, and buyers need to be cautious and conduct thorough inspections before making a purchase. Ethical dealerships will prioritize customer satisfaction and honesty in their transactions.