Error codes 18434/P2002/008194, Diesel particulate filter (Solution)

The error codes 18434/P2002/008194, along with P2001, are the most common DPF (Diesel Particulate Filter) error codes in VAG diesel vehicles. The diesel particulate filter no longer sufficiently fulfills its cleaning function - usually because it is overloaded with ash (maximum ash masses and their adjustment) and can no longer be regenerated. This is not a defect, but wear and tear.

When is the DPF too full? Values for typical DPF ash content.

What do the error codes 18434/P2002/008194 mean?
The engine control unit monitors the differential pressure across the DPF (using sensor G450) and calculates the soot load based on this reading. If the ash load exceeds a threshold, regeneration is no longer possible. The filter is "full" and needs to be replaced or professionally cleaned.

Typical symptoms:
- Engine check light and/or DPF (Diesel Particulate Filter) light illuminated.
- The motor is running in emergency mode (reduced power).
- Particle filter warning light is flashing.
- Automatic regeneration is no longer possible.
- In extreme cases, the vehicle may not be able to start (depending on the year of manufacture).
- Often combined with codes P2001 or P2463 (diesel particulate filter soot accumulation).

Most common causes:
- The DPF has excessive ash buildup (normal wear and tear after 150,000-250,000 km).
- Frequent short trips: Recovery is constantly interrupted.
- EGR valve is defective or not closing properly - increases soot production.
- Intercooler or its hoses leaking (hissing sounds, oil traces) - increases soot formation.
- Differential pressure sensor G450 is defective (reporting incorrect load values).
- Turbocharger oil leak - increased ash content.
- Leaking or worn injectors - incomplete combustion.

Diagnosis with VCDS:
- Auto-scan: Read error code P2002 from the engine control unit (ECU).
- Measurement blocks for DPF: Ash loading (grams or percentage), soot loading, differential pressure.
- Calculated soot mass: critical.
- Ash mass: Filter is too full.
- Check the differential pressure of filter G450 (setpoint vs. actual value).
- Check the date and mileage of the last successful regeneration.

Repair:
- Have the DPF professionally cleaned or verschandeln the DPF yourself - alternatively, replace the DPF, for example, in case of damage.
- Replace the G450 sensor if it is defective.
- Force DPF emergency regenerationPrevention:
- Driving long distances (regeneration requires approximately 20-30 minutes of uninterrupted operation).
- Use high-quality diesel fuel and the appropriate engine oil (low ash content).
- Prevent martens from damaging the car (e.g., by chewing on wiring for the SCR system and temperature sensors) by installing a wire mesh under the car, close to the ground.