Eolys system - problems and solutions
Eolys technology is an auxiliary solution used in diesel vehicles to improve the efficiency of particulate filters. It works by adding a special agent, Eolys fluid, which is injected from a tank and activates the regeneration process of the particulate filter. Although the principle used by this system allows accumulated soot to be burned off effectively, Eolys has its weaknesses, which become apparent after the first few hundred thousand kilometres of mileage.
Problems associated with the Eolys system
During operation, the Eolys system becomes increasingly vulnerable. Problems are often related not only to the FAP fluid itself, but also to additional components, such as worn dosing devices or electronic errors in the metering system. Sometimes the system blocks regeneration, causing the engine to go into emergency mode. Sometimes the driver only becomes aware of the problem after an indicator appears or there is a significant increase in exhaust emissions.
Main types of problems:
| Type of problem | Cause | Consequences |
| Low fluid level | Consumption due to mileage | Regeneration impossible |
| Tank failure | Mechanical damage | Leakage, fluid loss |
| Faulty meter | Software malfunction | Incorrect signals on the ECU |
| Damage to the metering pump | Wear or contamination | Injection cycle disruption |
As can be seen from the table, almost all problems are related to either costs or maintenance complications. All of this can be a serious reason for visiting a repair shop.
FAP and DPF fluid – problems and costs
The most common reason for visiting a service station is the need to top up or replace FAP fluid.
This is a special fuel additive that is not interchangeable with others (e.g. AdBlue). In most cases, its use is regulated not only by mileage, but also by the amount of fuel consumed. This is a special fuel additive that is not interchangeable with others (e.g. AdBlue). In most cases, its use is regulated not only by mileage, but also by the number of refills from the fuel tank, which is monitored by an electronic meter.
The fluid needs to be refilled every 120,000–180,000 km because it has a limited service life. Here is an approximate table of costs that a car owner may encounter:
| Costs | Approximate amount |
| New fluid (1 litre) | 90–175 PLN |
| Full tank refill | 350–660 PLN |
| Refilling at a workshop | 220–440 PLN |
| Resetting the counter in the ECU | 130–265 PLN |
Refilling FAP fluid is not a one-time operation, but a recurring procedure that must be performed during each service after a certain mileage has been reached. It should be noted that the fluid tank itself may also fail, which further increases the total cost of maintenance.
Disabling the Eolys system software
Given the high cost of maintenance and the complexity of the design, more and more owners are opting for a complete software deactivation of the Eolys system. This solution not only saves money, but also eliminates the risks associated with the error indicator, regeneration failure or injection malfunctions.
At STS, the Eolys deactivation procedure is performed using special diagnostic equipment without damaging the electronics. This ensures complete safety for the engine and other vehicle systems. The main advantages of this approach are:
- Savings on the cost of the FAP fluid itself, as well as on replacement services.
- No need to reset the counter or update the software after each service.
- Uninterrupted operation of the particulate filter without the influence of incorrect injection.
- Professional approach and STS warranty for every service — confidence in quality.
If you want to get rid of constant expenses and have a stable car — Eolys software disabling is a reliable solution.
Alternatives to the Eolys system
As the market changes and technology improves, there are several effective alternatives for owners of cars with the Eolys system. These are worth considering, especially if your car is no longer under warranty or you are planning to upgrade your FAP filter system.
- Switch to new-generation filters that do not require fuel additives.
- Replace the old Eolys system with a mechanically simpler model.
- Use AdBlue in vehicles that are compatible with this technology.
- Replace the particulate filter with a ceramic filter without liquid support.
- Complete removal of the filter (only for off-road or sports cars).
- Installation of software with new regeneration logic.
The choice of alternative depends on your driving style, car type and budget. In any case, it is best to consult a specialist.
Expert recommendations
Regardless of whether your Eolys system remains active or you are already planning to disable it, here are some practical tips from STS experts:
- Monitor the fluid level in the system and top it up in good time.
- Have your vehicle serviced regularly at a specialist workshop.
- Do not ignore the indicator on the instrument panel, even if it disappears after starting the engine.
- Perform preventive cleaning of the FAP filter every 100,000 km.
- Use only certified fluid for the DPF — this will extend the life of the system.
- Take into account the actual cost of refilling the fluid when planning your maintenance budget.
- If you choose to disable the system, only trust a proven service with experience.
These simple steps will help you maintain the reliability of your vehicle and avoid serious breakdowns on the road.
The Eolys system plays an important role in ensuring environmentally friendly exhaust emissions, but its maintenance becomes too burdensome over time. If you want to avoid regular checks, costs and repairs, contact STS — we will always offer you a modern solution with a quality guarantee and support.
