Tractor Fix-it Series, Ep. 1: Fixing Error Code "Error 1" on John Deere 4520

Here I run through the process of checking and cleaning your sensors, which turned out to be the problem. First thing I did before that was check and replace the transmission fuse, and when that didn't work, I checked all the connections on the underside of the tractor, and finally moved onto the forward/reverse sensors, which solved the peoblem!
Thanks for watching and if y'all have any questions, please post them in the comments and I'll do my best to answer them!