8 causes of engine fault light and how to handle it

1. Damaged high voltage wire, power distributor

Depending on the vehicle, different ignition systems (coils with high-voltage wires or distributors) may be used to supply power to the spark plugs. When one of the components of the ignition system fails, it will cause misfires, incomplete fuel combustion, reducing the vehicle's performance and potentially damaging the catalytic converter.

Solution:Check the high voltage wire connectors, check the coil or distributor.

2. Broken spark plug

Spark plugs have to work continuously for a long time under harsh conditions, the spark plugs will wear out the electrodes leading to poor ignition, fuel consumption and increased vehicle emissions. The worst case is the spark plug dies, cannot ignite, causing the vehicle to vibrate and weaken.

Solution: Check and replace damaged spark plugs; experts recommend replacing new spark plugs every 40,000km (with regular spark plugs) and every 100,000km (with Platinum or Inridium spark plugs).

3. Wind sensor failure

The air sensor measures the amount of air entering the engine and the ECU calculates the appropriate amount of fuel to be injected into the combustion chamber. When this sensor is not working properly, it will cause an imbalance in the air and fuel ratio, reducing engine performance.

Solution:Check the sensor connectors one by one; check for hidden wire breaks.

4. Oxygen sensor not working

The oxygen sensor measures the amount of unburned oxygen escaping from the exhaust pipe and tells the ECU to adjust the amount of fuel injected. If this sensor is damaged or not working, it can increase fuel consumption by up to 30%.

Solution:The diagnostic machine may indicate that the oxygen sensor is not working. However, do not jump to the conclusion that the sensor is bad, it could be a loose connector or a broken wire.

5. Thermostat failure

The thermostatic valve is responsible for keeping the coolant temperature at the right temperature for optimal engine operation by opening or closing to allow coolant to circulate into the engine. If this valve is stuck (open), the coolant temperature will not reach the optimal level for a certain period of time and the ECU will signal the light.

Solution: Check the level of dirt that causes the thermostat valve to jam, clean the dirt on the valve; if damaged, replace it.

6. Faulty exhaust filter

Normally, the exhaust filter is rarely damaged unless the high-pressure unit is malfunctioning, causing misfires (excess fuel) or the engine has problems (such as the engine eating oil, causing soot, clogging or blocking the filter). A damaged exhaust filter can cause the fuel signal to the control center to be incorrect, causing the fuel input to be incorrect, and the engine to work less efficiently.

Solution:The car needs to be brought to the garage for inspection. The technician will diagnose the condition or damage of the filter to clean or replace it.

7. Gas cap is loose or not tight

A loose or damaged fuel tank cap will cause fuel loss, increase fuel consumption and harm the environment. The EVAP Pressure sensor system (measuring the vapor pressure of the fuel in the tank) will detect abnormally low pressure in the tank and report an engine error.

Solution:Check the fuel tank cap; if the fuel pump is not tightened or the channel is loose, it can also cause fuel vapor to leak, causing the sensor to detect and report an error.

8. Fuel filter valve relay stuck

The EVAP system purge valve relay (also known as the EVAP valve, is a system that filters vapors released from the fuel tank or fuel injection system) is responsible for controlling the escape of gases from the fuel system. This relay works in cycles and can get stuck, causing the valve to stay open.

Solution:The relay is stuck or broken so replacement is the best solution.