P0400 - Exhaust Gas Recirculation (EGR) Malfunction (Solution)

Error codes: 16784/P0400/001024 - Exhaust gas recirculation (EGR) malfunction.

Possible symptoms:
- MIL (Malfunction Indicator Lamp) light illuminated on the instrument cluster.
- Power loss.
- The noise level of the engine idling sounds slightly "rougher".
- Emission limits are not being met.

Possible causes:
- Wiring/cabling to the AGR module is faulty or damaged.
- AGR module damaged/defective.

Note: VAG uses EGR modules that, in some cases, are equipped with plastic gears that are prone to long-term tooth failure. There are replacement parts for the AGR modules available from independent parts suppliers, which are significantly cheaper than those offered by the vehicle manufacturer's parts department.