The DEF level sensor, which is part of the DEF sending unit, measures the level of fluid remaining in the DEF tank. When the liquid level is low, the DEF level sensor sends a signal to the vehicle's ECU which then triggers the warning light on the gauges or panel.

How does a DEF quality sensor work?

Ultrasound waves are used in Diesel Exhaust Fluid (DEF) Quality Sensors, also known as Fluid Property Sensors, to detect the condition of DEF in a truck's tank. ... If DEF has been diluted with any kind of fluid, such as water, the density of the DEF will be changed and the Quality Sensor will detect it and alert you.

What is a DEF head sensor?

Essentially, the DEF head monitors the DEF system. The DEF head communicates the quality (or concentration of urea) of the fluid is within spec. It relates that there is, in fact, DEF in the tank (quantity). This part also reports the temperature of the DEF is in a safe range.

What does DEF do?

Diesel Exhaust Fluid (DEF) is a solution of urea and water that's injected into the exhaust stream of diesel vehicles to turn NOx gases (harmful emissions) into nitrogen and water. This system is called a Selective Catalytic Reduction (SCR) implemented by vehicle manufacturers to meet EPA emissions standards in 2010.

Can you drive without DEF?

If the truck is allowed to run out of DEF the engine's power is reduced, a solid red warning will be displayed and the vehicle speed will be limited to 5 mph until the DEF tank is refilled.

Q&A | Talking DPF Sensors and the DEF Sensor Shortage

Is DEF made from urine?

Diesel exhaust fluid is not made of urine, and if you are going to urinate in your SCR system, you're looking at having to pay some pretty hefty repair costs to clean and replace engine components once they have been contaminated.

How does a DEF system work?

Small quantities of diesel exhaust fluid (DEF) are injected into the exhaust upstream of a catalyst, where it vaporizes and decomposes to form ammonia and carbon dioxide. The ammonia (NH3) is the desired product which in conjunction to the SCR catalyst, converts the NOx to harmless nitrogen (N2) and water (H2O).

What causes a DEF pump to fail?

Dirt / Metal Contamination: Contaminated DEF can cause abrasion of the DEF pump. Dirt, rust or tank scale can occur with improper of DEF storage or handling (e.g. res-using disposable DEF containers). UREA Concentration (Dilution): Diluted DEF (too much water) reduces its NOx neutralization effectiveness.

Who makes DEF level sensors?

SSI Technologies, a designer and manufacturer of ultrasonic level, pressure and magnetic sensors and monitoring systems, announced an SCR System DEF combination sensor to monitor urea level, temperature and concentration.

Where is the DEF sensor located?

A DEF quality sensor is mounted on the side of the DEF tank. This sensor detects the Urea concentration in the DEF to confirm it is acceptable for effective dosing (approximately 32.5% Urea).

How do I fix poor quality?

A new DEF filter, EGR tune-up, and a fresh set of NOx sensors can go a long way. It can eliminate the potential of skewed sensor readings or poor EGR performance, and it can assure you that you'll have the correct information feeding the computer for future diagnosis if the problem continues.

What is the DEF head issue?

It directly relates to problem with the Diesel Exhaust Fluid (DEF) system that is a part of the emissions system that removes particulate matter from the diesel exhaust stream. This was the first stage of the problem, which can progress quickly and put the RV into "limp" mode that restricts vehicle speed to 5 mph.

How often should a DEF filter be changed?

Change the filter at least every 3 years. If you are putting more than 35k miles on a year, try to have it done every 100k miles. The manufacturers recommendation is safe and in no way wrong.

Does DEF go bad?

Because it doesn't include any preservatives, DEF does come with a shelf life. The good news is, it's a fairly long shelf life; DEF can usually be stored up to one year without any issues.

How long does DEF fluid last?

Diesel exhaust fluid normally has a shelf life of about two years. However, exposure to sunlight or sustained high temperatures can compromise it.

How much does it cost to replace a DEF system?

The cost of a replacement filter $2,500 -‐ $5,000. Professionally clean approximately $1,500. Recommended replacement after 200,000 miles. All in DEF / SCR Filter adds approximately $ .

Does DEF ruin engine?

If DEF enters the fuel system and spread throughout the engine it will ruin the diesel engine eventually. The fuel system lines are not compatible with DEF and slowly corrode and over time.

How do you clean a DEF system?

Containers, funnels and other equipment that will contact or store DEF should be cleaned before use. Wash thoroughly and rinse with distilled water. If distilled water is unavailable, rinse with tap water, then rinse with DEF.

Is DEF used for Regen?

JLandry TDR Member. jacknife, On the 2013/14 models, diesel is indeed used to elevate exhaust temperature in the DPF (Diesel Particulate Filter) to burn off accumulated soot during a regen cycle.

Will DEF freeze in my truck?

Diesel Exhaust Fluid or DEF Fluid

Whether in storage tanks or in equipment, DEF can freeze and possibly cause issues. As temperatures drop below 12°F, DEF will begin to solidify and not work as intended.

Is DEF bad for diesel engines?

While it's good for the environment, the water and urea mixture can result in the formation of crystals that can plug up fuel filters, damage aircraft engines, and result in engine failure. DEF should never be used as an additive for any fuel, diesel or aircraft, and is sprayed directly into exhaust systems.

Can you drive a diesel without DEF?

SCR Systems

Modern trucks will not run without the DEF. Hence the need for diesel truck owners to check their fluid levels frequently. Reducing emissions should be everyone's goal. Maintaining your vehicle would also reduce emissions and DEF consumption.

What happens if I put water in my DEF tank?

If you put water in an EMPTY DEF tank, there will be no urea injected into the exhaust to convert to ammonia. Ammonia is an essential requirement to eliminate NOX (Oxides of Nitrogen) via the SCR (Selective Catalytic Reducer).

Do new diesels need DEF?

Most new diesel trucks are equipped with selective catalytic reduction (SCR) systems that use diesel exhaust fuel (DEF) to meet EPA emission standards.