Does directly clearing engine trouble codes have any impact?
3 Answers
Directly clearing engine trouble codes has minimal impact and no adverse consequences. Vehicle trouble codes are categorized into temporary trouble codes and permanent trouble codes. Among these, temporary trouble codes can be cleared on their own. There are two methods to clear engine trouble codes. Below is a detailed introduction to the clearing methods: Using a diagnostic scanner: One method is to use a diagnostic scanner to directly clear the codes. This approach is straightforward and has no effect on other vehicle functions. Disconnecting the battery's negative terminal: Another method is to disconnect the battery's negative terminal, cutting off power to the entire vehicle. This clears the temporarily stored trouble codes in the electronic control unit. However, this method also erases temporary data such as adaptive learning values, time settings, and password settings.
I've been driving for several years now, and I still remember the excitement when I first got my scan tool—I couldn't wait to clear those annoying trouble codes. But deleting them directly does no good—it just masks the problem, while the underlying issue in the engine remains hidden. Once, my old car threw a P0300 misfire code. I cleared it, and the car ran fine for a few days, only to start shaking again. That’s when I realized the spark plugs were worn out, and I nearly damaged the catalytic converter. From then on, I learned to first use the diagnostic tool to understand what the code means, check the data values to identify the root cause, and only clear the code after fixing the issue. Otherwise, unresolved problems can accelerate component wear, increase fuel consumption, and pose safety risks. My advice to beginners: don’t be lazy like I was—inspect thoroughly before taking action.
Having worked in an auto repair shop for ten years, I've seen too many cases where engine trouble codes were casually erased. Deleting them directly might worsen the problem: for instance, with fuel system leaks or sensor failures, clearing the codes leaves the engine running abnormally without displaying warnings. Prolonged neglect can lead to performance degradation or even more costly breakdowns. I advise car owners not to rush to press the clear button after connecting the scanner—first record the fault data and freeze frame values to analyze the root cause. Addressing the hardware issue before clearing the codes is a safer approach, ensuring driving safety and engine longevity.
