T5 Engine Light + Poor Performance: Cam Timing Issues

Had the exact same symptoms on my T4 2011 gasoline model. The crank sensor was failing intermittently, causing engine management issues. When the crankshaft position sensor starts failing, it cant properly detect engine timing, leading to poor performance and increased fuel consumption. The diagnosis revealed the timing chain had stretched slightly, affecting the synchronization between camshaft and crankshaft. This meant the engine control unit wasnt getting accurate position data. The repair involved replacing both the timing chain and crank sensor since they work as a system. This is considered a serious issue because incorrect timing can potentially cause engine damage if left unaddressed. The symptoms match perfectly, flashing check engine light, power loss, and poor fuel economy are classic signs of crank sensor failure or timing issues. The job took about 6 hours at the shop as they needed to access the timing chain cover. Its not a simple sensor swap since they need to verify proper timing after installation. Would suggest finding a shop that specializes in engine management systems, as proper diagnosis requires specific diagnostic equipment.

Thanks for sharing that experience. Had nearly identical problems with my VW last year. The timing was way off causing misfires and the check engine light kept flashing. After checking reference values, my mechanic confirmed it was the crankshaft sensor failing to sync properly with the camshaft. Did you run into any other issues afterwards? Would be good to know if the repair held up well. Also wondering what the total cost was for parts and labor, helps give others a rough idea what to expect for similar repairs.

Since getting the work done last year, the repair has held up perfectly. The mechanic resolved the crankshaft to camshaft reference value issue completely. No more flashing engine light or performance problems. In total, fixing the defective crankshaft sensor and related timing issues came to 340€. This included parts, labor, and testing to ensure proper synchronization after the repair. The price was fair considering the technical expertise needed to diagnose and fix these engine management problems correctly. The timing chain is still performing well with no stretching or sync issues. Fuel economy returned to normal and the engine runs smoothly. When dealing with crank sensor problems, its crucial to address them promptly to prevent potential engine damage from incorrect timing signals. The key was finding a shop with proper diagnostic equipment to accurately measure the timing chain and sensor values. Quality parts and precise calibration make all the difference for these types of repairs.

Thanks everyone who shared their experiences. I finally got this sorted out last week. Took it to a specialist shop that actually identified the root cause, turned out the crankshaft sensor was failing intermittently, throwing off the engine timing. The mechanic showed me the diagnostic readings showing misfire patterns and irregular engine synchronization values. They replaced both the crank sensor and timing chain since there was some wear. Total bill came to 390€ including parts and labor. Car runs perfectly now, no more flashing engine light, power is back to normal, and fuel economy has improved significantly. Really glad I got a second opinion from a shop that actually knew what they were doing with engine management systems. For anyone facing similar issues, make sure to get it checked by someone who specializes in engine diagnostics. The initial shop wanted to replace multiple parts without proper testing, which would have cost way more without fixing the actual problem.