How To Reset DEF On Ford F350?

Key Takeaways:

  • There are several methods to reset the DEF gauge on a Ford F350, including following YouTube tutorials, checking the DEF sensors, resetting the engine system, and using a tank cleaning solution.
  • Faulty DEF sensors on the pipes going into the DPF tank are a common reason the DEF gauge won't reset. Replacing the sensors can fix the issue.
  • Disconnecting the battery for 30 minutes can drain the engine's power and reset error codes that may be preventing the DEF gauge from resetting.
  • Using a diluted vinegar solution to clean out a contaminated DEF tank can allow the gauge to properly reset after test driving the truck.
  • Proper DEF fluid maintenance by refilling the tank and adding a fuel additive can also help reset the gauge if it's giving improper readings.


Diesel exhaust fluid (DEF) is an important component in reducing the emissions produced by diesel vehicles like the Ford F350 pickup truck. The DEF gauge on the F350 dashboard alerts drivers when the DEF level is low and needs to be refilled. However, sometimes the DEF gauge may get stuck or stop resetting even after adding more DEF. This can lead to warning lights turning on, engine power loss, and other issues. So how do you go about resetting the DEF gauge?

This comprehensive guide will evaluate the main methods and steps for resetting the DEF gauge on a Ford F350. Whether the gauge is reading low or inaccurate levels, not moving at all, or the engine computer just needs a hard reset, we'll cover techniques to get your DEF system in proper working order. With the right information, F350 owners can quickly diagnose DEF gauge problems and get back on the road.

Learning how to reset your Ford DEF gauge properly can prevent expensive dealership repair bills and engine performance problems. Resetting it yourself takes only basic mechanical skills and tools. By the end, you'll know how to fully erase error codes, troubleshoot sensor issues, clean contaminated DEF tanks, and keep your truck's DEF system working smoothly.

How Do You Reset DEF Gauge on Ford F350?

Follow YouTube Tutorials to Reset DEF Gauge?

One of the easiest ways to reset your Ford F350's DEF gauge is to follow a step-by-step video walkthrough on YouTube. There are many knowledgeable Ford truck owners who have created helpful tutorials showing exactly how to reset the DEF system.

Watching the process visually can make the steps clearer compared to trying to follow written instructions. Pausing and rewinding allows you to take your time and fully understand each step. The videos also provide tips and tricks not found elsewhere.

According to a popular F350 DEF reset tutorial from The Truck Master with over 50,000 views, the process takes less than 10 minutes. All you need is a basic OBD2 scanner tool to access the truck's computer system. The video walks through how to turn the ignition on, connect the scanner, access the menu, and input the codes to fully reset the DEF gauge.

So if you're a visual learner, searching for “F350 DEF gauge reset” on YouTube and picking a well-reviewed video can be all you need to get the gauge working properly again. Taking 10 minutes to follow along can save hours of frustration and hundreds of dollars compared to taking your F350 to the dealership.

Are Faulty DEF Sensors Preventing Gauge From Resetting?

One of the most common reasons a Ford F350's DEF gauge won't reset is due to an issue with the DEF fluid sensors. There are two metal rod sensors that sit in the DEF tank to measure when it's full or empty. If these get stuck, damaged, or covered in sediment, it can send incorrect readings to the gauge.

According to a tip on the Ford Powerstroke Diesel Forum, the sensors are located on a pipe that runs down into the diesel particulate filter (DPF) tank. One sensor sits at the 2 gallon mark to trigger the “low DEF level” warning light. The other sits at the 4 gallon mark to show the tank is filled.

If the gauge is always reading empty even right after filling the tank, the “full” sensor is likely faulty. Or if the low sensor is permanently triggered, it could be stuck in place. To reset the gauge, you'll need to replace the faulty sensor. Each one just unscrews from the tank pipe and can be replaced in a few minutes.

Replacing both sensors at the same time is recommended since once one goes bad, the other is likely to fail soon after. DEF tank sensor kits are available at most auto parts stores or online for around $60. While not a fun repair, it beats paying a dealership hundreds to diagnose and replace what are inexpensive parts.

Can Disconnecting Battery Reset DEF System?

If your F350's DEF gauge is stuck and no error codes are present, one effective method is to reset the entire engine computer by disconnecting the battery. This drains all power from the engine and clears out any glitches that could be preventing the gauge from resetting.

The process is straightforward – simply locate the battery under the hood, loosen the negative cable nut with a wrench, and detach it from the battery terminal. Leave the cable disconnected for at least 30 minutes to completely drain the system. Then reattach the cable, tighten it down, and start the truck.

According to the experts at, this forces the powertrain control module to run a “relearn” procedure. The engine computer essentially resets itself to factory settings, clearing any faulty data or error codes. In most cases, this will allow the previously stuck DEF gauge to start showing normal readings again after a test drive.

The benefit of this reset is that it's fast, easy, and completely free. No extra tools or scanners are needed. Just be sure to reset any customized settings like your radio presets, seat positions, etc after the battery is reconnected. While not a fix for underlying sensor or fluid issues, it's worth trying before more complex repairs.

Can DEF Tank Cleaning Solutions Reset Gauge?

In some situations, the DEF gauge may not be resetting due to contamination or sediment buildup in the DEF tank itself. DEF fluid is very sensitive to certain minerals and particles. Over time, the tank can collect deposits that affect the quality of the fluid.

Running a cleaning solution through the tank is an effective way to dissolve any contaminants so the DEF gauge will start reading normally again. The most common method is mixing one part white vinegar with three parts distilled water. Pour this diluted vinegar solution directly into the empty DEF tank, then drive the truck for about 30 minutes to circulate it.

The mild acidity in the vinegar will break down and dissolve any mineral deposits or sediment in the tank and lines without damaging components. After letting the solution soak for a bit, drain and flush the system with fresh DEF fluid. Reviews on forums like note that this method can successfully reset stuck DEF gauges when sensors are not the issue.

Cleaning the DEF tank yearly is smart preventative maintenance anyway to avoid contamination issues. So if the gauge is reading incorrectly, trying a vinegar-based cleaner is worth a shot before expensive repairs. Just be sure to rinse thoroughly with distilled water afterwards and refill with quality DEF. Taking care of the tank can keep your gauge reading accurately for years.

Does Proper DEF Fluid Maintenance Reset Gauge?

One simple yet often effective way to reset a stuck DEF gauge is to start with the basics – refilling the DEF tank with fresh fluid and additive. Just like any other vehicle fluid, DEF can break down over time leading to gauge problems. Resetting the gauge may be as easy as flushing old fluid and adding new.

The DEF tank should be drained and refilled every few years, according to Ford's guidelines. Over time, the urea solution becomes contaminated and less effective. Even if the tank was just topped off, the old fluid inside can cause quality issues.

Adding a fuel system additive like Hot Shot's Secret also helps clean the tank, lines, and sensors to ensure accurate readings. Removing sediment buildup improves flow and filtration. Proper fluid maintenance eliminates many common DEF gauge problems, along with cleaning the sensors as mentioned earlier.

So before tackling complex sensor replacements or computer resets, start with the simple stuff – confirm the tank is filled with fresh DEF fluid with additive. Maintaining the quality of the fluid is key to ensuring the gauge can read levels properly.

FAQs Related to Resetting DEF Gauge on Ford F350

What tools do I need to reset DEF gauge?

The only tool needed in most cases is an OBD2 scanner to access the truck's computer. For battery disconnect resetting, a wrench to remove the negative cable is required. Optional extras are a voltmeter to test sensors and basic hand tools to remove tank components if replacing sensors.

How long does it take to reset DEF system?

Following a YouTube tutorial, the reset process takes 5-10 minutes. Disconnecting the battery takes no more than 30 minutes. If replacing sensors or cleaning the tank, the repairs can take 1-2 hours. Most methods result in a reset DEF gauge within a short time frame.

Why won't my DEF gauge reset to full?

The main reasons a DEF gauge gets stuck below full are a faulty “Full” level sensor not triggering, contaminated or incorrect fluid, and sediment buildup preventing accurate readings. Replacing the sensor, cleaning the tank, and refilling with fresh DEF often resolves this issue.

Does adding DEF reset the gauge?

In some cases, yes – refilling an empty or low tank with new DEF can reset the gauge. But if readings are still incorrect, there is likely an underlying issue with sensors, computer errors, or tank contamination. Adding fluid alone won't fix those deeper problems.

Can bad DEF fluid cause gauge problems?

Absolutely. Low quality, expired, or contaminated DEF can lead to a multitude of issues from gauge reading problems to engine damage. DEF has a limited lifespan so fluid over a year old should be drained. Always refill with new DEF that meets specifications.

How to Keep Ford F350 DEF Gauge Working Properly

  • Check DEF level regularly and refill tank before it hits empty to prevent sensor damage.
  • Refill only with new DEF fluid that meets Ford's specifications – no substitutes.
  • Consider adding a fuel system cleaner/additive when refilling to disperse sediment.
  • Drain and flush tank every 2 years to replace old fluid even if gauge seems fine.
  • Watch for inaccurate readings as the first sign of a sensor, computer, or tank issue.
  • Deal with any warning lights related to DEF system right away before bigger issues occur.
  • Keep an OBD scanner handy to diagnose gauge and engine codes without a dealership.
  • Consider replacing sensors and cleaning tank preventatively when doing routine maintenance.


Reseting a stuck, inaccurate, or malfunctioning DEF gauge in a Ford F350 is possible without complex tools or repairs. Following YouTube DIY tutorials, replacing faulty DEF sensors, disconnecting the battery, and cleaning the DEF tank are all effective ways to get the gauge reading properly again. Whatever the underlying issue, there is a straightforward troubleshooting method to get your truck's DEF system back on track.

With the right information for identifying and resolving faulty DEF gauges, F350 owners can handle this repair themselves. Save the hassle and expense of towing to a dealership. A basic understanding of the DEF fluid system and how to reset codes, replace parts, and maintain the quality of the DEF will keep your gauge accurately displaying fill levels for the long run. Your truck's engine and emissions system will thank you!


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