VW Phaeton Timing Issue Causing Power Loss & Poor MPG

Having dealt with very similar symptoms on my 2013 VW Passat, I understand your concern. The symptoms you describe match exactly what I experienced, engine light, power loss, and increased fuel consumption. After taking it to the workshop, they diagnosed a faulty crank sensor which was causing incorrect readings between the crankshaft and camshaft timing. The repair involved replacing the crankshaft position sensor and clearing the fault codes, costing 340€ total including parts and labor. The good news is that it wasnt a timing chain issue in my case. The faulty sensor was causing the ECU to receive incorrect timing signals, which led to the performance issues. After replacement, all symptoms disappeared completely. To help provide more specific guidance, could you share: Current mileage on your Phaeton, Any specific error codes from the engine light, Whether symptoms appeared gradually or suddenly, If the engine makes any unusual noises These details would help confirm if your issue matches what I experienced with my similar VW engine. Also, have you noticed if the problems are worse when the engine is cold or at operating temperature? This can be a telling indicator for sensor-related issues versus mechanical timing problems.

Thanks for checking about my situation. My Phaeton has 121371km on the clock, and the symptoms started gradually over the past few weeks. I ran a diagnostic scan yesterday which showed error code P0016, pointing to the crankshaft position sensor circuit. The issues seem most noticeable when the engine is cold, especially during the first 10 minutes of driving. No unusual noises so far, which makes me hopeful its not a timing chain problem. I think your experience with the crank sensor might be exactly what Im dealing with. Going to schedule a workshop visit next week to have them check the sensor specifically. Just wondering if you remember how long the repair took in your case? Trying to plan whether I need a rental car or if its a quick fix.

Thanks for providing those details about your Phaeton. Error code P0016 and the cold-start symptoms match exactly what I experienced with my crank sensor issue. The repair on my Passat was surprisingly quick, the whole job took about 2 hours at the workshop. Since your symptoms are identical to what I dealt with, including the gradual onset and cold-engine behavior, it strongly suggests a failing crankshaft position sensor rather than a timing belt or mechanical problem. The cam sensor readings become erratic when the engine is cold because thats when the failing sensor struggles most to maintain accurate signals. For reference, my repair timeline went like this: 1 hour diagnostic confirmation, 30 minutes to replace the crank sensor, 30 minutes for computer reset and test drive You likely wont need a rental car since its typically a same-day repair when the issue is sensor-related. Just make sure the workshop has the correct sensor in stock before bringing it in. Quick tip: If you notice the symptoms getting worse before your appointment, try to avoid heavy acceleration as the incorrect timing signals can cause the engine to run rich and waste fuel.

The crankshaft sensor information you shared seems really helpful since my symptoms match yours so closely. Just booked the workshop for next Tuesday and mentioned the crank sensor specifically. They confirmed they can get the part beforehand and expect it to be a 2-3 hour job max. Another symptom I forgot to mention, my engine also occasionally stutters a bit at idle when fully warm, which they said could also be related to the camshaft and crankshaft timing signals being off. The timing chain itself still looks good through the inspection window, so Im feeling more confident its just the sensor. Good to know I wont need a rental car. Ill take it easy on the accelerator until then, as suggested. Thanks for the detailed insight about your repair experience, really helped narrow down the likely cause versus a more serious timing chain replacement.