How to Manually Reset the Engine Malfunction Light?
2 Answers
If the engine malfunction light is on, you can follow these steps: First, check whether the engine is running normally and whether there are problems such as shaking or black smoke. If so, try not to start the engine again. It is especially important to note that you must not start the engine if the red light is on. If the engine can be started, turn it off for 5-10 minutes. Then, without pressing the brake, press the start button once or turn the car key halfway to the 'on' position without pressing the clutch. After the car is powered on, it will perform a self-check function. Wait for 5-10 seconds and observe whether the malfunction light on the dashboard turns off. If the malfunction light does not turn off, please visit a service station as soon as possible to identify the cause. The service station can use a portable diagnostic tool to read the fault code, obtain fault information, and perform targeted repairs. There are mainly 7 reasons why the engine malfunction light is on: Sensor malfunction: The sensors mentioned here include the water temperature sensor, crankshaft position sensor, air flow sensor, intake temperature sensor, oxygen sensor, etc. When these sensors are damaged, have poor contact, or their signals are interrupted, the car's ECU cannot accurately obtain engine data, which will cause the engine malfunction light to turn on. Fuel quality issues: If you do not add fuel and engine oil as required by the manufacturer, it may cause engine wear and lead to the malfunction light turning on. Poor combustion of the air-fuel mixture: Poor combustion of the air-fuel mixture can cause engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the malfunction light will turn on as a warning. Spark plug failure, ignition coil failure, fuel pump failure, and fuel line blockage can all cause poor combustion of the engine's air-fuel mixture. Turbocharging issues: The intake turbocharging pipeline and turbocharger can also cause the engine malfunction light to turn on. The most common issue is turbocharger damage, accompanied by symptoms such as oil leakage, high oil consumption, reduced power, metal noises, or blue/black smoke from the exhaust pipe. Intake issues: If there is a problem with the car's intake system, it may cause engine pipeline blockage, and in severe cases, the engine malfunction light will turn on. If the air filter is dirty and not cleaned regularly, it can lead to intake problems. Exhaust issues: Exhaust faults can also cause the engine malfunction light to turn on. The rear oxygen sensor, three-way catalytic converter, exhaust camshaft, and bearing faults are all causes of exhaust problems, with the three-way catalytic converter being the most common. Using leaded gasoline, lead- or silicon-containing lubricant additives, physical damage to the three-way catalytic converter, or faults in the engine fuel supply system can easily cause three-way catalytic converter failure. Anti-theft system malfunction: If the car's electronic anti-theft system malfunctions or the anti-theft controller does not match the engine electronic controller, the anti-theft system can also cause the engine to malfunction and the engine malfunction light to turn on.
I've driven quite a few cars, and the check engine light often comes on in older vehicles. The simplest manual way to reset it is by disconnecting the battery for a few minutes. The specific steps are: first turn off the engine, open the hood to locate the negative terminal connection, loosen and remove it with a wrench, wait about 10 minutes for the ECU to reset, then reconnect it and start the engine - the light might go off. But this is just a surface-level fix. The hidden danger is that if the real issue isn't addressed, like clogged fuel injectors or a failed catalytic converter, the light will come back on quickly or the problem might worsen. I recommend pairing this with an OBD scanner to read the trouble codes for a reliable solution. For prevention, regularly replace spark plugs and air filters. I've handled it this way three times and it worked each time, but you need to be mentally prepared to deal with potential underlying issues and not delay addressing major problems.
