Just recently got a new o2 sensor installed and the car has been running perfectly sense. After about 40-50 miles of driving, the CEL came on reading code P0411. Issues with the car, absolutely none except when I first start it and reverse the car shakes a bit. Low coolant light is on. Other than that, the car runs fine, anyone have an idea how to fix this code or problem? Thanks

 

So I let the car sit overnight so I could give it a cold start and listen for the vacuum noise, and that checked out fine. By looking at the hoses and everything, it all seemed good. My question is, when I took it to the mechani, the connector with the red and black lines on the left of the secondary air pump was unplugged, and I replugged it in, but that was over 2-300 miles ago. Just an update if anyone can point me to possible problem.