The best way to turn off the check engine light on a Nissan is to find out the engine code and have the problem fixed. The check engine light turns off automatically when the issue causing the light to turn on is resolved.
Disconnecting the vehicle's battery can turn off the check engine light temporarily. This can clear codes that relate to the car's emissions, causing it to fail a smog test.
The check engine light generally comes on because the car's computer has detected a problem with one of its systems. The vehicle stores a code that corresponds to the specific issue. Codes are standardized across all cars and brands. There are a few hundred possible codes.
A dealership for the car brand can read the code and recommend repair options if necessary. Repairs may also be covered under warranty if the car is new enough. An independent mechanic can also read the code and make repairs, often at a lower price than a dealership. Certain repair shops and auto part stores scan cars free of charge. Scan tools can also be purchased for as low as $25. More advanced tools may cost several hundred dollars. Keeping up with the maintenance on vehicles is the best way to prevent the check engine light from coming on.