P0236 OBD Code in 2007 VW Touareg 3.0 V6: Intermittent Turbo Boost Pressure Issue

Hi everyone, I'm seeking help with a recurring OBD2 fault code P0236 on my 2007 Volkswagen Touareg 3.0L V6 diesel model. The code indicates an issue with the turbo boost pressure sensor. My mechanic recently replaced the turbo pressure sensor, but the problem has returned and remains intermittent. Symptoms include: - When coming to a stop, engine RPMs drop unexpectedly. - In some cases, the tachometer 'hunts' — fluctuating between 1000 and 1500 RPMs. - Visible smoke may emerge from the exhaust during these episodes. The fault is not constant. After turning off the engine, switching it off completely (removing the key), and restarting, the issue may resolve for several days or even up to two weeks before recurring. Occasionally — though not always — the glow plug warning light flashes, and an orange message appears stating 'Engine Fault. Workshop'. This warning sometimes appears before I even start moving. I need this vehicle next month to tow a heavy load to France, so any insight or troubleshooting steps would be greatly appreciated. Thanks in advance for your help! Rob