My Dad owns a 2005 Chevy Trailblazer. My Mom was driving doing errands and the engine light came on. My Dad drop it off the Chevy dealership that day. He came back and they don’t know what’s going on. They ran a engine diagnostic test and this what what the Chevy technician put down. My Dad said he checked the oil beginning of November and it was good. They don’t know what’s going on and he doesn’t know what to do. The oil going somewhere.
2 different codes but likely one core issue. The fact that the engine oil was so low it wasn’t registering is the first concern. A quart every thousand miles is a lot of consumption. Do yourself a favor and do a proper oil change and monitor the level closely for a month. Check it weekly and see what the use really is. Most likely you have a vacuum leak which is the P0171. Pretty common issue. If the oil is really dropping as much as the tech notes say, you either have a pretty good external leak which you will see bu looking under the car or it’s being burned which is a much bigger problem. A leak down test will confirm this. Just so you know… P codes are federally mandated for all car manufacturers and they are the same for every car made since 1996. In other words a P0171 has the same diagnostic path for a Chevy Silverado as does a Lamborghini. You can look these up on the internet for clues but not exact diagnosis.