How to Clear Engine Trouble Codes?

[GabrielleLee]

You can pull the fuse to clear the trouble codes. If that doesn't work, go to a repair shop and use a diagnostic scanner to clear the trouble codes. If the codes cannot be cleared, repairs will be needed.

[SaraAnn]

When the engine warning light came on, I found it quite a headache. First, I bought an OBD-II scanner, which wasn't expensive, and plugged it into the diagnostic port under the steering wheel. After turning it on, it displayed a P0420 code, indicating low catalytic converter efficiency. I looked up some information and suspected it might be due to an aging oxygen sensor, so I replaced it with a new one myself. After the repair, I selected 'clear fault codes' in the scanner's menu, and the light went off immediately. The whole process was quite simple, saving money and learning some skills in the process. However, it's important to note that if you clear the codes without fixing the underlying issue, the light may come back on quickly, or worse, damage the engine. Regular inspections and maintenance are better than waiting for minor issues to turn into major repairs. I recommend that beginners consult more experienced friends or check online tutorials, and never ignore that yellow light—it's your car crying for help.

[LukasLee]

In the past, when cars had issues, we used to disconnect the negative terminal of the battery for a few minutes before reconnecting it. This method did reset the ECU and temporarily turn off the warning light, but the light would come back on if the problem wasn’t fixed, and it could also erase radio settings. Nowadays, using an OBD scanner is much better—I keep one handy, plug it into the port, and clear codes with a single click, which is more reliable. The scanner can also read specific trouble codes, like P0300 indicating a misfire, which might mean the spark plugs need replacing. Diagnosing before repairing is key; otherwise, just clearing codes carries risks. To save money, you can buy an affordable scanner online for a few dozen bucks—it’s easy to use. Avoid blindly disconnecting the battery, especially in newer cars with sensitive electronics, as it can cause errors. Always wear gloves for safety when working on your car, and avoid touching hot engine components.

[DiAdam]

Eliminating the malfunction indicator light (MIL) actually lies in addressing the root cause. The illuminated light is a signal from the ECU detecting abnormalities, such as intake manifold leaks or sensor failures. Simply using a scanner to clear the codes only treats the symptoms, not the root issue—you must disassemble and inspect the problematic components. Last time I encountered a P0171 (System Too Lean) code, I first checked for wiring damage, replaced faulty parts, and only then cleared the codes, after which the light naturally turned off. Ignoring faults while driving increases fuel consumption, damages components, and even risks sudden engine stalls at high speeds. Whether you buy tools or hire a technician, never just aim to turn off the light without fixing the car. Safety comes first—if you detect an issue, stop and inspect immediately. Don’t delay until it becomes a major problem.