Here's the proper procedure:
1. Obtain a Diagnostic Trouble Code (DTC): You need to know *why* the check engine light is on. You can do this in a few ways:
* OBD-II Scanner: This is the best option. Buy a relatively inexpensive OBD-II scanner from an auto parts store or online. Plug it into the OBD-II port (usually under the dashboard) and it will read the trouble codes. The codes are usually a series of numbers (e.g., P0171).
* Auto Parts Store: Most auto parts stores will read the codes for free. Just bring your vehicle in.
2. Identify the Problem: Once you have the DTC(s), look them up online (many free resources are available) or in a repair manual specific to your 2003 Dodge Ram 1500. This will tell you what the code means and the likely cause.
3. Repair the Problem: This is the crucial step. Based on the DTC and your research, fix the problem. This might involve replacing a sensor, fixing a leak, or addressing a more significant mechanical issue. You might be able to do some repairs yourself, or you may need to take it to a mechanic.
4. Clear the Code (After Repair): Once you've fixed the problem, you can clear the code using your OBD-II scanner. The scanner usually has an option to clear the codes. After clearing the code, drive the vehicle for a short while. If the problem is truly fixed, the light should stay off. If it comes back on, the problem hasn't been solved, and you need to re-diagnose.
Warning: Simply disconnecting the battery or using a code reader to erase the codes without fixing the underlying issue is not a solution. The check engine light will likely return, and the problem could worsen, leading to more expensive repairs down the road. Ignoring the light can also lead to failure to pass emissions testing.
