Trying to "reset" the computer without addressing the root cause will likely just result in a failed emissions test again. The check engine light is there to inform you of a problem that needs fixing. Ignoring it will not solve the issue and might cause further damage.
Here's what you should do instead of looking for a reset:
1. Check the Check Engine Light: If your check engine light is on, get the trouble codes read. An auto parts store usually offers this service for free. The codes will tell you *what* the car's computer detected as a problem.
2. Address the Problem: Based on the trouble codes, you can address the underlying issue. This might involve:
* Replacing a faulty sensor: Oxygen sensors, mass airflow sensors, and other sensors are common culprits.
* Fixing a leak in the exhaust system: Exhaust leaks can cause inaccurate readings.
* Repairing a malfunctioning catalytic converter: This is a major component of the emissions system.
* Replacing spark plugs and wires: Worn-out ignition components can affect emissions.
3. After Repairs: Once you've fixed the problem(s) identified by the trouble codes, you should drive the car for a while (usually at least 50 miles, under various driving conditions) to allow the computer to relearn your driving patterns and monitor the system's performance. Then, retest your emissions.
There's no magic reset button. The computer monitors emissions continuously. If the underlying mechanical or electrical issue isn't resolved, the computer will continue to flag it. Focusing on the repair, rather than a reset, is the only reliable way to pass emissions.
