The controller is called the Powertrain Control Module (PCM). On this model it will be located near the glove box. It is made by Denso Corp. These units and the software that control the system are proprietary and tampering with any of the components or parts or software is against the law in most counties. In the US tampering with any part of the system is a federal crime with a stated fine of $25,000 per occurrence. Changes to the software can be made; the software then is to be re-certified to ensure that it meets tailpipe emission limits. That said there are many who have figured out how to get around the regulators. The other option is to repair whatever has failed that is causing the trouble codes to set. The CEL does not set for no reason.