Reduced engine power and car shuts off

ANSWER : Hi there. If there is carbon build up on the valves in the engine then that can cause a rough running condition and even a check engine light but that will not usually cause the vehicle to stall. It sounds like you have another issue going on here. From my experience with this vehicle most of the time this is caused by a voltage issue. Most of the time it is a loose or dirty ground connection or an issue with the ignition switch. I usually start by scanning the computer for codes to see what is coming up as that can assist in finding the issue. If the codes do not help then the electrical system would need to be diagnosed to see where the power is being lost. If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the check engine light is on and why the vehicle is stalling] https://www.yourmechanic.com/services/car-is-stalling-inspection

ANSWER : Hi there. Check the battery and alternator to the vehicle. With all of the electrical issues that you are having, it sounds as if the battery is not charged and making the engine stall out due to lack power. Check the battery for a 12.6 volt reference and load test the battery. If the battery fails, then replace the battery. If the battery passes, then check the alternator and see if its putting out the full amount of amps. If you need further assistance with electrical issues, then seek out a professional, such as one from Your Mechanic, to help you.

ANSWER : The code P1516 is is for the throttle position sensor. It looks like the car’s computer is putting the engine in "failsafe mode" to prevent the car from being driven much further. A technician would need to examine the system firsthand to accurately diagnose the code and make the correct fix. A certified technician from YourMechanic can come to your car’s location to thoroughly inspect the car and let you know how to best proceed.

ANSWER : Hi there. There are a lot of things that can cause this on your 2012 BMW M5. I usually start by scanning the computer for codes to see what comes up. If there are not codes then I load test the alternator and the battery to see if they are failing. Low voltage in the electrical system will cause this. If that is fine, then it is usually caused by a failing throttle body. I have seen a lot of these fail due to the motors in them hanging up. If the problem is only happening intermittently, this can make the issue hard to duplicate, but you can still have tests done on the car. If you are going to have this fixed, consider YourMechanic, as a certified mechanic can come to your home or office to test the vehicle and diagnose the Engine Malfunction Light.

ANSWER : Hi there. Most of the time, reduced engine power is caused by a restriction of fuel, or the throttle body’s inability to efficiently mix air and fuel. This could be caused by a failing mass air flow sensor, EGR valve or other fuel system components. Since the check engine light is on, you should have a professional mechanic complete an inspection at your location to determine what codes are stored and which components require repair. This should resolve your issue.

ANSWER : Hello. It sounds like you may have an issue with your throttle position sensor. This sensor sends a reference voltage to your power-train control module, which uses that to determine ignition timing and fuel trims. If the power-train control module is not detecting the proper signal from the throttle position sensor, the engine may not accelerate properly. It’s probably a good idea for you to have a professional mobile mechanic come to your location and complete a car is slow to accelerate inspection first, so they can pinpoint what is causing this issue to occur and they will recommend the right repairs be completed.

ANSWER : If the reduced power problem was intermittent, a mechanic would not have had a reason to check the cam belt to see if, for example, the belt jumped timing which itself is a cause of reduced power. Shop practice varies widely insofar as customer notification of "required" maintenance. On many vehicles, the list of items involved in such maintenance can be extensive and so unless the customer makes a specific request to be brought up to date, or you have a specific service agreement, you are probably not going to get a careful and complete accounting. The best thing to do is rely on the published maintenance schedule for your car. That schedule is accessible from the Owners Manual and is published on the Internet, too. In lieu of that, if you desire you can book a vehicle inspection and a certified mechanic will come to your location and both review the maintenance schedule with you to see what has or has not been done in the way of required maintenance and/or the mechanic will simply thoroughly inspect the vehicle to determine what may be required. If you have further questions or concerns as you decide what to do, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you get the best possible results.

ANSWER : It is possible that your vehicle’s PCM has failed. This is somewhat of a common problem amongst many GM vehicles. If the computer has failed, this could be one of the reasons that no trouble codes are appearing and the fact that the problem is intermittent. It is possible that the computer is somehow getting overheated and by stopping the vehicle for a short period of time, the PCM cools down allowing the vehicle to run again. I would recommend having your PCM tested for proper function by a certified technician with experience in computer diagnostics.