Q: Since mechanic changed engine oil on dashboard flashes service engine soon

The variable valve timing VANOS system on your car can become sticky over time. Particularly if you are not changing the oil diligently. It is a hydraulically operated device that advances the camshaft using engine oil pressure under certain conditions. It has a number of very small orifices and tightly fitting parts that can be plugged and jammed by the smallest of debris. The failure may or or may not be related to your oil change. The recommended oil for your car is a 5/30 synthetic, so if the mechanic used something heavier, you might be able to solve your problem by changing to the correct oil, but I doubt it. Usually the only recourse is to take the VANOS pieces apart and clean the system out. If you want to know more specifically what has to be done, You can contact your mechanic to have a technician come to your home or office to check out your car and recommend a fix.