Renault Scenic / Grand Scenic Diesel Particulate Filter DPF

The Diesel Particulate Filter (DPF) on Renault Scenic and Grand Scenic with diesel engines (Euro 4 and higher) is a ceramic component located in the exhaust system after the catalytic converter. It captures harmful fine soot particles produced by combustion to reduce pollution, retaining up to 99% of solid particles like carbon, hydrocarbons, sulfates, and metallic oxides.

The DPF filtration works as follows:

• Exhaust gases pass through porous ceramic walls, trapping soot on a large surface area.
• Passive regeneration occurs on highways at high engine load where gas temperatures reach 550-600°C, burning soot naturally.
• Active regeneration is controlled by the engine ECU during city driving or low load, injecting extra fuel to heat the catalytic converter and burn soot, monitored by temperature, pressure differential, and oxygen sensors.
• Some Renault FAP models use additives to lower soot combustion temperature by accelerating oxidation.

The DPF is integrated post-turbo with the catalytic converter in Scenic 1.5, 1.9, and 2.0 dCi diesel engines.

Signs indicating DPF issues include:

• Engine or DPF warning light illuminated on the dashboard.
• Loss of engine power due to increased exhaust backpressure.
• Unstable idle, increased fuel consumption, and visible black smoke.
• Diagnostic trouble codes such as P2463 showing critical soot levels often requiring replacement.
• Frequent clogging in urban driving due to insufficient heat for passive regeneration.

If these symptoms occur, have your vehicle checked at a garage with proper diagnostic tools.

Recommended maintenance and repair procedures include:

• Forced regeneration by driving at 2500-3000 rpm on a motorway for 20-30 minutes to heat exhaust gases and burn soot.
• Chemical cleaning using specialized DPF cleaners that dissolve soot deposits (performed carefully to avoid sensor contamination).
• DPF replacement, which is a relatively easy job involving removal from the exhaust line post-catalytic converter. ECU recalibration might be required.
• Regular diagnostics via OBD systems to monitor pressure differentials and sensor status using apps like myCarly.
• Prevention by avoiding short urban trips, using premium diesel fuel, and performing regular oil changes with low-ash oil.

Always consult a professional garage to ensure proper handling and avoid damage to the turbo or ECU.

Common problems and their main causes include:

• Soot blockage: Predominantly due to urban, short-distance driving limiting passive regeneration.
• Cinder accumulation: Long-term use beyond 100,000 miles requiring DPF replacement.
• Warning lights: Faulty pressure or temperature sensors causing error codes.
• Power loss: High backpressure from clogged DPF increasing exhaust resistance.

Proper diagnosis and timely maintenance are key to preventing costly replacements.

DPFs generally last between 150,000 and 250,000 kilometers depending on driving habits and maintenance. Early and regular upkeep, including proper regeneration and cleaning, can significantly prolong the DPF's operational life.

Severe clogging or neglect can lead to permanent damage to the turbocharger and engine control unit, so professional garage checks are recommended at the first sign of issues.

Some Renault diesel particulate filters are designed to work with additives that lower the temperature required to oxidize soot, thus aiding regeneration. Additionally, using premium fuels or treatments such as shell nitro+ diesel for a couple of tanks may improve combustion quality and help keep the DPF cleaner.

• Discuss with your garage about suitable additives and their compatibility with your DPF system.
• Always follow manufacturer recommendations to avoid damage to sensors or the exhaust system.

When consulting a garage, consider these important questions:

• Have you checked the pipes between the DPF sensors for leaks or blockages ?
• Have the differential pressure and temperature sensors been tested or replaced if faulty ?
• Is forced regeneration possible and recommended at this stage ?
• Can chemical cleaning be performed safely without damaging sensors or the catalytic converter ?
• What is the estimated cost and process if a DPF replacement is necessary ?
• Are there preventative maintenance tips specific to my Scenic diesel model ?

Asking these will help you get a clear diagnosis and the best solution for your DPF-related issues.