Your dash monitor is probably shutting off when you turn the key off. Your VCM still holds power for a few seconds and cannot communicate with the monitor therefore causing your P07 code. The newest trucks keep power to the monitor so the two can communicate with each other. This code is not harmful to the but is more of just a pain because it keeps coming up all the time. Nissan makes a sub harness to install to keep power to the dash monitor for about 3 seconds.