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

(238)

Rating Summary
224
5
4
0
5
224
5
4
0
5

Jason

15 years of experience
344 reviews
Jason
15 years of experience
Nissan Armada V8-5.6L - 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!!!

Nicholas

11 years of experience
585 reviews
Nicholas
11 years of experience
Chrysler 300 V6-2.7L - 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

Tony

40 years of experience
12 reviews
Tony
40 years of experience
Cadillac Escalade EXT V8-6.2L - Warning Light is on - Stockton, California
Good,mechanic helpful ,smooth move but quick, friendly patience and deep experience as a mechanic,as a customer I recommend Tony Crockett if you need a mechanic.

Brent

8 years of experience
56 reviews
Brent
8 years of experience
Jeep Grand Cherokee V6-3.7L - Warning Light is on - Lithonia, Georgia
On time for appointment. Knowledgeable, he explained what he was doing & then explained his findings to me. Later he sent a text with the diagnostic findings,

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 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.
What Does the Tire Pressure Warning Light Mean?
The tire pressure light warns you when one or more of your tires is low on pressure and needs to be set to the correct PSI.
Top 12 Most Common Car Problems and Issues
Completing Completing routine service and maintenance is vital to keeping your car, truck, or SUV running strong. At times, however, car issues will arise, and every vehicle will display certain warning signs. To reduce the potential for breakdown, and expensive...

Related questions

EPC light, PCV leak and loss of power for 2009 Audi A3 Quattro
Hello. It is common for the PCV valve (https://www.yourmechanic.com/services/pcv-valve-hose-replacement) to fail on this engine, and some of the time, it will cause the rear main to leak also. As for the power control, this means that there is an electrical...
Speedometer and gears failed; car towed - 2009 Kia Borrego
It seems like the problem is one the shop may have not experienced just yet or they may have found a big problem and are trying to work with Kia directly for warranty or recall information. Take the vehicle back...
Hi temp low oil and low oil pressure warnings come on
Hello. The warning lights that are coming on can be caused by a few different things. If all three have come on at the same time then it is very likely that the oil has run low. Aside from causing...

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