Nope. This means that the code has been deleted from the car computer's memory. And if it re-appears after you have cleared it, that means the problem indicated is persistent. However if you clear it and it doesn't re-appear, then chances are that this was due to some other reason and is not really a problem. For example, a bad starter motor might trigger bad CMP sensor code P0340 which isn't really the case when the car is not starting due to a bad/weak starter. Same can be true for many other problems. An error code gives you the best estimate to start your investigation and may not always be 100% accurate however combine it with the symptoms that are mentioned in the service manual and usually you are able to pin-point the exact problem with your vehicle.