error code P0847

As was already stated, it is very common. ALWAYS best to test and confirm, but these switches can fail intermittently, and when testing , be fine. Two tips-1) the 3rd pressure switch is the one on the front of the trans case near/under 2 speed sensors and the cooler lines. accessed from underneath the vehicle, I usually get a box wrench on it, crack it loose, then it spins out easy by hand. Put the new one in , using a new crush washer(GET BOTH FROM HONDA DEALER), ONLY SNUG IT, DO NOT OVER TIGHTEN! wOULD THEN also recommend a simple 'drain & fill, I would stress using Honda ATF, Get 3 quarts, it generally takes about 3.7 quarts. Check level on level ground AFTER it has been driven 10 miles , to fully warm up the fluid. Check after 30 seconds, with engine OFF.

You most likely have a pressure switch failure that isn't that uncommon, however it's not a recommendation without getting that checked and verified.