I recently bought my first bass, which is a Squier P Bass, after learning guitar. The problem with the bass is that it will quite often randomly have zero or extremely low output when I plug it in after letting it sit for a while. Only once did it drop to zero while I was playing. I believe the problem lies in the pickups after troubleshooting with different cables and amps, but I'm not 100% sure.
So far, the ways I’ve managed to get the bass working again include:
Waiting a bit until the output fixes itself.
Pressing on the pickups until it works.
Flipping it upside down.