Im so new here so y'all will probably ignore this thread, but I have come across a few reasons why you will get the ESC  Error and fixed all so  far..
Since I purchaced my P3P with said error i did my googling and read everything i could find. 90% of the time the said fix was new Motherboard, so i bought one and installed it.. ESC Error still there... The fabled firmware fix from the MODS did nothing... Pulled all 4 motors off and tested them and they all "Appeared to be good, they wernt they were all bad actually, the test was bad as they were all producing the same voltage on each leg when spun up to 2500rpm but the voltage produced was too low. Replaced the motors and all was good, ESC Error gone, drone flying like a champ.. Recieved another  P3P with the same error, went through all the tests and found a bad wire in the motor feed on one of the motors. Seems the older motors are 2 core feed wires and oner of the cores was broken that put too much strain on the 2nd and it failed also..... Um thats all i got so far, will add or delete as other projects progress,,,

Just dont assume the ESC error is any one issue it could be the Motherboard it could be Frimware it could be Motors or it could be a broken wire

How did you test each motor? Did you backdrive the shaft and measure the voltage at the contact points?

Hi. Thank you for creating this informative post and sharing your personal insights regarding this concern. It is good to know that the previous trouble with the ESC was resolved. Just a friendly reminder that DJI does not recommend to do any DIY repair to ensure the drone is properly repaired and tested. Thank you and safe flying.