What are the reasons for the engine emission fault light alarm?
2 Answers
Reasons for the engine emission fault light alarm include: 1. False alarm: Impact during driving, tampering with certain engine connectors, or temporary ECU signal interruption; 2. Poor mixture combustion: This can lead to engine carbon buildup or knocking issues, which the engine oxygen sensor will detect; 3. Sensor issues: When sensors such as water temperature, crankshaft position, air flow, intake temperature, or oxygen sensors are damaged, have poor contact, or experience signal interruption, the vehicle's ECU cannot accurately obtain engine data; 4. Maintenance issues: Failure to perform regular maintenance and poor driving habits can increase the burden on engine operation; 5. Fuel quality issues: The fuel added to the car has specific grade requirements, and failure to meet these requirements can cause engine wear.
I also had a car with this issue before. When that yellow check engine light came on, I got really nervous and immediately searched online. It turned out there could be multiple causes. The most common one is a faulty oxygen sensor - if it inaccurately detects oxygen levels in the exhaust, the warning light activates. It could also be a clogged or failed catalytic converter, which is responsible for purifying exhaust gases; if blocked, emissions exceed standards. Additionally, fuel system problems like dirty or malfunctioning fuel injectors, or a clogged fuel filter can trigger the light. Even minor issues like intake system leaks or faulty mass airflow sensors can be related. I later learned this is quite common - many friends' vehicles have experienced it. Untreated, it may lead to decreased fuel efficiency, reduced engine power, and potential failure in annual inspections. So when the light appears, it's best to visit a repair shop promptly to read trouble codes with an OBD scanner for accurate diagnosis before fixing.
