VW Polo Flashing Check Engine + Poor Performance Fix

Had the exact same symptoms on my 2003 VW Golf TDI. Initially thought it was a timing belt issue, but diagnostic tests confirmed a faulty crank sensor. The engine light started flashing during highway driving, and the car showed the same sluggish behavior with increased fuel consumption. The reference values between the crankshaft and cam sensor were indeed off, causing the engine management system to receive incorrect timing signals. This is actually quite serious as it can lead to complete engine failure if left unchecked. The crank sensor plays a crucial role in engine timing and fuel injection. In my case, the sensor was completely replaced along with its wiring harness, as corrosion had damaged the connection. The repair also included checking the timing chain tension since these components work together. After replacement, both performance and fuel economy returned to normal, and the engine light cleared. Your mechanic is on the right track with the diagnosis. Would strongly recommend getting this fixed soon, as continuing to drive with mismatched sensor signals can cause more extensive engine damage.

Thanks for sharing your experience. It is reassuring to hear someone had similar issues with their VW. I actually went ahead and had my car fixed last week after reading about potential engine synchronization problems. The mechanic replaced the crank sensor and cleaned the entire area around it since there was quite a bit of oil residue affecting the readings. Just wondering, how much did you end up paying for the repair? Also, have you noticed any other issues since getting it fixed? My engine light has stayed off since the repair, but I am still monitoring fuel consumption closely.

Thanks for the follow up. Since getting the crankshaft sensor replaced and having the engine synchronization corrected, my Golf has been running perfectly. The repair cost me 340€ total, which included cleaning the surrounding area and checking all reference values between crankshaft and camshaft. No issues at all in the past 18 months, the engine light has remained off and fuel consumption returned to normal within about 2 tank fills. The mechanic explained that once the crank sensor was replaced and properly calibrated, the engine management system could again receive accurate timing signals. Keep monitoring your fuel consumption, but you should see it normalize soon. The improved reference values between components typically result in better overall engine performance. Getting this fixed was definitely worth the investment to prevent more serious engine damage down the line.

I took my car back to the mechanic last week and had everything fixed. The total bill came to 280€, which included replacing the cam sensor and cleaning the surrounding area. The mechanic showed me the old sensor which was covered in oil residue, explaining why the reference values were off. After two full tanks of fuel, I can confirm the consumption is back to normal. The engine feels much smoother now, especially during acceleration, and the engine light has stayed off. Looking back, the timing between the crankshaft and camshaft was indeed the core issue, just as my mechanic initially suspected. Really glad I did not wait longer to fix this, as the mechanic mentioned it could have led to timing chain problems if left unchecked. The car runs like new now, and I will definitely keep up with regular maintenance to avoid similar issues in the future.