- DPF failures trigger dashboard errors, power loss, speed limits, and higher fuel use.
- Professional cleaning costs 200-500 lei, while new DPF can exceed 5,000 lei.
- Most blockages come from frequent short trips under 10 km preventing regeneration.
- DPF self-cleaning relies on passive regen; occasional active regen raises fuel use.
Diesel car owners often wonder whether they can perform periodic cleaning of the diesel particulate filter (DPF) themselves, or if professional service is mandatory. This dilemma is justified, given that the DPF is a crucial component for meeting emission norms, and a new filter can cost well over 5,000 lei.
DPF filters have become standard on all modern diesel vehicles in Euro 5 and above, and keeping them in optimal working condition is essential for engine performance and compliance with current regulations.
Importance of Regular DPF Cleaning
Diesel particulate filters require regular attention to function properly. The primary role of the DPF is to capture soot particles from exhaust gases and burn them off periodically through the regeneration process.
When the filter is not cleaned regularly or when automatic regeneration fails, it becomes progressively clogged. The consequences can be serious:
- Error codes appearing on the dashboard
- Significant reduction in engine power (often 30-50%)
- Limitation of top speed by activating protection mode
- Increased fuel consumption
- Risk of complete DPF failure requiring replacement
Professional periodic cleaning costs between 200 and 500 lei, while a new DPF can cost over 5,000 lei for standard cars and even 8,000–12,000 lei for premium models with large engines.
Main Causes of DPF Blockage
Frequent short trips
The most common cause of DPF blockage is predominantly using the vehicle for short trips, under 10 km. In these conditions, the engine never reaches the optimal temperature required to trigger automatic regeneration.
Associated technical faults
Blockage of the DPF can be a symptom of deeper problems:
- Faulty DPF sensors that do not correctly detect the particle load
- Incorrect oil quality or quantity in the engine oil
- Turbocharger problems that affect combustion parameters
- Defective fuel injection system causing incomplete burning
- Exhaust gas temperature sensor that does not function correctly
It is crucial to understand that a blocked DPF is usually a symptom, not the root cause of the problem. Simply cleaning the filter, without identifying and addressing the underlying issue, will lead to repeated blockages.
Self-cleaning Process of the DPF
Passive regeneration
Under normal conditions, the DPF cleans itself through passive regeneration, which occurs when:
- Exhaust gas temperature exceeds 550°C
- The vehicle runs continuously on highways or national roads
- The engine operates in optimal range for an extended period (minimum 20–30 minutes)
Active regeneration
When passive regeneration is not sufficient, the car’s ECU initiates active regeneration by:
- Additional fuel injection to raise the temperature
- Adjusting the timing of injections
- Increasing the idle speed
This process can raise fuel consumption by 0.5–1 L/100 km during regeneration.
Manual Cleaning — Possibilities and Limitations
What the owner can do
-
Forced regeneration by driving
- Drive on the highway for 30–45 minutes
- Keep the engine speed between 2500–3000 rpm
- Avoid frequent stops
-
Using DPF additives
- Specialized products that lower the regeneration temperature
- Use in the fuel tank according to the instructions
-
Regeneration via diagnostics
- Use an OBD tester to initiate forced regeneration
- Requires technical know-how and specialized equipment
Limitations of DIY cleaning
Professional cleaning involves processes that a typical owner cannot perform:
- Complete removal of the filter from the exhaust system
- Cleaning with specialized equipment (ultrasound, vapors, chemical agents)
- Pressure testing and verification of structural integrity
- Recalibration of the system after reinstall
Why It Is Not Recommended to Remove the DPF
Legal aspects
Removing or bypassing the DPF is illegal in Romania for Euro 5 and higher vehicles:
- Fines between 580–1,160 lei for the owner
- Seizure of the vehicle registration certificate
- Inability to pass the ITP (periodic inspection)
- Issues when reselling the vehicle
Technical consequences
- Emissions increase by 10–15 times
- Engine map modification can affect reliability
- Loss of the manufacturer’s warranty
- Insurance problems in case of an accident
Recommendations for Maintaining DPF Health
Preventive driving style
- Take weekly long trips of at least 30 km on fast roads
- Let the engine warm up before short-distance driving
- Avoid turning off the engine during active regeneration
- Use high-quality fuel from reputable stations
Proper maintenance
- Change the oil at the recommended intervals with correct specifications (Low SAPS)
- Periodically check the injection system
- Monitor turbocharger operation
- Monitor temperature sensors
When to call a specialist
- When the DPF warning light lights up on the dashboard
- When engine power drops
- When forced regeneration no longer works
- When error codes related to the aftertreatment system appear
The conclusion is that while there are some preventive measures a owner can take, professional cleaning remains the safest and most effective method for keeping the DPF in optimal working condition.