What Does the Fuel Filter Warning Light Mean?

Diesel engines are quite different from their gasoline counterparts. Besides not using spark plugs, just about every 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 doesn’t work very well as a 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 the fuel and water 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.

Some vehicles may empty the water automatically or you may have to empty it manually. 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.

What the fuel filter warning light means

Inside the fuel filter is a fluid level sensor that keeps track of the amount of water that has been collected. Once the level starts reaching maximum capacity, the fuel filter warning light will illuminate to let you know to empty the filter.

On 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 could mean that the drain is blocked and the system can’t empty itself. A code will be saved on the computer to help you identify the cause of the problem. Have the car checked out with diagnostic scan tool to find the saved code or codes.

Don’t ignore this warning light or the system will fill with water and start leaking it to the engine. Once the water has been drained from the filter, this warning light should go out on its own.

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

While it’s not an emergency when the light first comes on, it is important that you get the filter drained as soon 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 change out the fuel filter at the right service intervals as draining the water will not remove all the particulates that are caught in the filter.

Our certified technicians are always available to assist you in diagnosing any problems with your car’s fuel filter and they can drain or replace your fuel filter for you.


Next Step

Schedule Warning Light is on Inspection

The most popular service booked by readers of this article is Warning Light is on Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Warning Light is on Inspection reviews

Excellent Rating

(199)

Rating Summary
187
5
4
0
3
187
5
4
0
3

Jason

15 years of experience
344 reviews
Jason
15 years of experience
Nissan Armada - Warning Light is on - Mineola, New York
Excelente. Jason es todo un profesional con mucho conocimiento en la mecanica, buena persona educado y amigable. Gracias Jason.
Ford Taurus - Warning Light is on - Jamaica, New York
Very Professional definitely takes his time to find out exactly what’s the problem with the car! I was up and running in no time ! Will definitely recommend Him to anyone having issues with cars!!!

Travis

13 years of experience
497 reviews
Travis
13 years of experience
Volkswagen Beetle - Warning Light is on - Stillwater, Minnesota
Unbenoest to me when you change a battery on a 18 yr. old car you also need more than a code reader to reset the new battery.
Audi A8 Quattro - Warning Light is on Inspection - Minneapolis, Minnesota
Very helpful and very knowledgeable will be using this service again thank you Travis for everything trumbs up

Nicholas

11 years of experience
472 reviews
Nicholas
11 years of experience
Chrysler 300 - Warning Light is on - Durham, North Carolina
Excellent diagnostician. Knowledgeable and caring. Created a desire for him specifically, to do the job. Hope we get him every time!
Honda Accord - Warning Light is on - Garner, North Carolina
I was very happy with Nicholas and his knowledge and expertise about diagnosing the issues with my car. He is honest, reliable and professional. He is now my Mechanic that I will call on for all my car's needs.I will also recommend him to my friends whom have been taken advantage of by other car shops as I have been, and are looking for someone honest , that will not take advantage of them Thank you so much Nicholas for resolving my issue with my car. I feel relieved and happy with the outcome

Eduardo

19 years of experience
457 reviews
Eduardo
19 years of experience
Chevrolet Equinox - Warning Light is on Inspection - Houston, Texas
He arrived way early take his time and ran his diagnostic and i was satisfied at the end of his work great job

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

What Does the Parking Assist Indicator Light Mean?
A parking assist system helps your car park when it may be tricky to do so. If the light is flashing, dirt may be blocking the sensors from working.
What Does the Steering Lock Warning Light Mean?
The steering lock indicator light means your steering wheel is locked and can not be moved, usually until the vehicle's keys are present.
How Long Does a Fuel Filter (Auxiliary) Last?
The The fuel tank of your vehicle is where all of the gas that you put in your filler neck goes. Over the years, this tank will start to pick up a lot of dirt and other trash. It is...

Related questions

What is a throttle body filter

Code P0068 can have to do with the Throttle Position Sensor. It can also be due to a Mass Air Flow sensor fault. Usually this code can be set due to a vacuum leak, either somewhere in the air intake...

My abs light came on after I got my wheel bearing fixed.

Hi there. Check the wheel bearing to see if the wheel speed sensor was plugged in. Those indicator lights will come on when the sensor is left unplugged. As for the engine having a misfire, check the spark plugs and...

What does the Brake Warning Light on the dash mean?

The Brake Warning Light on the dash of your Altima should come on briefly when you first crank the engine. It should turn off quickly afterward, though. If it doesn’t turn off, it can indicate a couple of different things....

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com