2002 Volkswagen Golf Variant P0402 Code: Exhaust Gas Recirculation Flow Excessive - Diagnosis and Fix

Hi, I'm experiencing a persistent OBD-II fault code P0402 on my 2002 Volkswagen Golf Variant (1.6L gasoline engine). The code reads: "Exhaust Gas Recirculation (EGR) Flow Excessive Detected". The local repair shop has checked the system and found no obvious issues. Previously, I replaced the EGR return pipe, but the P0402 code returns within 2-3 days of resetting it using both an OBD-II scanner and a smartphone app. My engine runs smoothly under normal conditions with no performance issues. However, at low speeds (50–70 km/h), especially during traffic lights, the idle becomes unstable and fluctuates. Diagnostic data from the vehicle shows: - Engine Load: 10.19% - Long-Term Fuel Trim Bank 1 (LTFT1): +3.12% - Short-Term Fuel Trim Bank 1 (STFT1): 0.0% - Engine Coolant Temperature (ECT): 79°C - Fuel System Status: Open-loop due to engine load or fuel cut during deceleration Despite the absence of visible damage, the P040或2 code persists. I'm wondering what could be causing this EGR flow issue and whether it's related to a faulty sensor, clogged EGR valve, or another component. Any insights from owners of 2002 Golf variants with similar issues would be greatly appreciated. Thank you! — Ingemar