Audi A7 Diesel Particulate Filter DPF 1 (I) (2010-2018)

The Diesel Particulate Filter (DPF) is a crucial component of the exhaust system in diesel engines, including the Audi A7. Its main purpose is to trap fine particles and soot produced during diesel fuel combustion to prevent their release into the atmosphere and reduce environmental pollution.

In the Audi A7, exhaust gases generated after combustion first pass through the catalytic converter, then enter the DPF. The ends of the filter block gases and direct them through a porous ceramic substrate that traps most of the fine particles. Cleaner exhaust gas finally exits through the exhaust pipes.

There are two filter variants with functional differences:

• DPF: Located closer to the engine; burns soot by increasing gas temperature.
• FAP: Located mid-exhaust system; uses special catalytic substances for combustion.

Both serve the purpose of reducing particulate emissions but function differently.

The DPF should ideally be replaced every 100,000 km, although with regular regeneration its lifespan can extend to 150,000–180,000 km. Preventive maintenance includes adding a FAP additive to the fuel tank, which helps clean the filter and prevents premature clogging.

DPF regeneration is an automatic self-cleaning process that burns off the accumulated soot. It is controlled by the engine’s electronic control unit and only occurs under specific conditions such as:

• Sufficient fuel in the tank
• Properly functioning sensors
• Non-blocked EGR valve
• High exhaust gas temperature

The driver can also force regeneration manually by driving steadily with high and constant engine speeds over a long distance.

Symptoms indicating a failing or clogged DPF include:

• Engine warning light illuminated on the dashboard
• Specific DPF warning light on
• Loss of engine power
• Exhaust gases unable to exit properly

When soot accumulation reaches about 50 grams, the filter is considered blocked, and automatic regenerations may stop working.

Clogging occurs when the filter's automatic regeneration is not activated due to short trips, low engine RPM, sensor faults, or gradual soot build-up. The main solutions are:

• Replacing the DPF with a new unit (costly option)
• Professional cleaning of the DPF (recommended and practical)
• Removing the DPF (illegal and non-compliant with environmental regulations)

Professional cleaning restores the exhaust system's performance without altering original engine parameters and avoids the high cost of replacement. Common cleaning techniques include:

• Chemical washing: soaking the unit in a special solution to dissolve soot
• Cleaning without removal: pouring cleaning liquid through sensor holes to flush the filter
• Full disassembly cleaning: allows thorough cleaning and inspection

For an Audi A7 with about 150,000 km, professional cleaning is generally the best method for DPF maintenance and longevity.