VW Caddy Turbo Failure Causing Multiple Engine Issues

Had the exact same symptoms on a 2004 VW Passat TDI. The check engine light kept triggering due to boost pressure sensor readings being inconsistent. After checking the air intake system, found the boost sensor connector was corroded and had a loose pin. The whistling noise and jerking during acceleration are classic signs of boost leaks or sensor issues. In my case, the engine light triggered because the engine control unit received incorrect pressure sensor data, causing the turbo to malfunction. A proper diagnostic revealed two issues: Corroded electrical connection at the boost sensor, Cracked vacuum line near the sensor The fix required: Cleaning and repairing the sensor connector, Replacing the vacuum line, Resetting the engine control unit This was not a major repair but leaving it unfixed can damage the turbo and waste fuel. The symptoms match your description precisely, poor idle, reduced power, increased fuel consumption, and that characteristic whistle under load. Suggest getting the boost sensor and its connections checked first before replacing parts. Often the issue lies in the wiring or vacuum lines rather than the sensor itself.

Thanks for sharing your experience. I had similar boost sensor troubles with my Caddy last year. The check engine light kept flashing and turbo response was terrible. Your fix sounds spot on, wish I had known about checking connections first. Did you remember roughly what the total repair cost was? Also curious if youve had any other turbocharger or pressure sensor issues since getting it fixed? Mine has been running fine but always good to know what to watch out for.

Thanks for asking about the costs. Was happy to get mine sorted properly without major expenses. The repair came to 95€ total, mainly labor costs for tracing and fixing the faulty cable connection at the boost pressure sensor. Since having the bad boost sensor connection repaired, the car has run perfectly with no turbo or intake manifold issues. The engine control unit now gets accurate pressure readings, so the turbo boost works as intended. The previous symptoms, jerky acceleration, whistling, and high fuel use, all disappeared after the fix. For preventive maintenance, its worth regularly checking the intake system and boost sensor connections, especially the wiring and vacuum lines near the turbo. Corrosion in these areas is common and can trigger similar problems if left unchecked. Been over a year now with no further boost-related problems. The repair shop did a thorough job testing the pressure sensor system before and after the fix to ensure everything was working correctly.

Finally got my Caddy sorted! Took it to a new mechanic who actually knew what they were doing. The check engine warning was driving me crazy but they diagnosed it right away, exactly what you described with the boost sensor connection. Found a cracked vacuum line and corrosion on the sensor wiring. Total bill came to 120€ which seemed fair considering the first shop charged more and fixed nothing. They cleaned all the connections, replaced the vacuum line and reset the system. Car runs like new now, no more whistling or jerking during acceleration. Fuel consumption is back to normal too. Such a relief to have it properly fixed. The mechanic showed me what to look out for with the turbo system and pressure sensor connections, so hopefully can catch any future issues early. Really glad I asked here first instead of just replacing parts blindly. Saved me from getting ripped off again and helped point the new mechanic in the right direction.