Fuel filter warning light (Only for Diesel-Powered Vehicles) means that the water-trap in the fuel level is full and needs to be emptied. If the warning lamp illuminates when the engine is running this indicates there is excess water in the fuel filter.

Diesel engine uses fuel to lubricate high-precision engine components. Unfortunately, trace amounts of water can be found in diesel fuel and it needs to be removed before it gets to the engine.

Water is not a good lubricant and it could cause excessive wear on the engine if it made its way through the fuel system. To prevent this, diesel fuel filters are designed to separate water from the fuel and collects it at the bottom of the filter before it heads to the engine. The water is collected and must be emptied out occasionally, otherwise it will start to pull through the filter and make its way to the engine.

If the water that has collected in the gasoline filter is not emptied at the appropriate intervals, it may cause damage to the fuel system and other components. When the ignition switch is switched to the “ON” position, the Fuel Filter Warning light will glow for a few seconds before turning off completely.

A warning indicator on the dash will let you know when too much water has been collected and the fuel filter needs to be emptied. Some vehicles may empty the water automatically or you may have to empty it manually.

How fuels filter warning light work?

A fluid level sensor inside the gasoline filter monitors the quantity of water collected. Once the level starts reaching maximum capacity, the fuel filter warning light will illuminate to let you know to empty the filter.

On a manual systems, a valve at the bottom of the filter will let the water drain out once opened. If your filter empties automatically and the light comes on, it indicates that an error or malfunction has been detected and it needs to be checked out as soon as possible. This warning light may indicate that the drain is clogged and the system is unable to empty itself. A code will be saved on the computer to help you identify the cause of the problem. Check the vehicle using a diagnostic scan tool to locate the stored codes.

Don’t ignore this warning light or the system will fill with water and start leaking it to the engine. This warning light should turn off on its own after the water has been emptied from the filter.

Is it safe to drive with the fuel filter warning light on?

While it’s not an emergency when the light first turns on, it is important that the filter be emptied as quickly as possible. Waiting too long will let the water build up and eventually let it get to your engine where it can cause some serious damage. Remember to replace the gasoline filter at the proper service intervals since draining the water will not remove all of the particles trapped in the filter.

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