How to solve the problem of OBD light staying on?
4 Answers
The solution for the OBD light staying on: Read the fault code through the instrument and clear it based on the fault code. The meaning of OBD translated into Chinese is the On-Board Diagnostics system. The automatic diagnostic system mainly checks the operation status of the engine and monitors whether the vehicle's exhaust emissions exceed the standard. Once the vehicle's exhaust emissions exceed the standard, the OBD warning light will immediately illuminate. When the OBD light on the vehicle comes on, it indicates that there is an issue with the vehicle's emissions, which needs to be inspected immediately. There are many reasons that can cause vehicle emission faults, with the main reason being engine failure. The cause of the fault needs to be investigated one by one.
My car's OBD light has come on several times, and each time I first try to check it myself. Most of the reasons are minor faults in the emission system, such as a dirty oxygen sensor or impurities in the intake system. The simplest way is to buy an OBD scanner, plug it into the port under the dashboard to read the fault codes, like common codes such as P0420 or P0171. Just clean or replace the problematic parts. If you lack experience, don't push yourself—take it to a professional repair shop for a technician to diagnose. They use advanced equipment for more accurate results. Remember not to delay, as a constantly lit light may affect engine performance or even increase fuel consumption. Regularly checking the air filter and spark plugs can prevent issues. A maintenance check only costs around two to three hundred yuan, saving you from bigger expenses later. If the light suddenly comes on while driving, slow down and pull over to check the water temperature and oil pressure—safety first.
Having repaired cars for twenty years, I can tell you that a constantly lit OBD light is no small matter. It usually indicates emission-related issues, such as a clogged catalytic converter or faulty sensors. Don't guess blindly—visit a reliable repair shop to scan the codes with a diagnostic tool. The tools aren't expensive; you can even buy a basic version to try at home. Common codes like P0135 or P0300 often point to oxygen sensor or spark plug problems. Minor issues can be fixed by clearing the codes, but permanent faults require part replacements. I recommend checking the fuel system and exhaust pipes for leaks, as carbon buildup is common in dusty areas. If the light stays on with engine shaking, stop driving and get it fixed immediately. Repairs can cost anywhere from a few hundred to over a thousand, but proper maintenance can prevent this. Don't ignore it—long-term issues will damage your car and cost you more.
As a new car owner, I panicked when my OBD light came on but learned a trick. It's usually caused by sensor issues or software faults. First, buy a Bluetooth OBD scanner and connect it to a phone app to read the codes. Common codes like P0442 indicate a small leak in the evaporative system. Try cleaning or resetting it. If that doesn't work, visit a 4S shop—technicians handle it professionally. The cost is low; replacing a small sensor costs just a few hundred. The light indicates excessive emissions—don't delay for environmental reasons. Fixing it can also improve fuel efficiency. Regularly check oil levels and filter conditions, and maintain your car to reduce issues. If the light comes on, avoid high-speed driving—pull over safely to check. Simple maintenance can often fix it.
