your car battery. But disconnection is only recommended under the most extreme circumstances. You should only do so if you have the experience needed to be safe. Certain car models might not let you disconnect the battery without specialized tools found at licensed dealerships or maintenance shops...
The Engine Control Module (ECM) serves as the brain of your vehicle, supervising and adjusting key elements of engine performance. Therefore, appropriate care and maintenance, including resetting when necessary, are crucial to ensure optimal operation. Common signs indicating a need to reset your ECM...