1, yellow oil pump stop valve (pump core) is damaged. After the pump core is blocked or worn by dirt, it is impossible to pump oil, even if the motor rotates, it is impossible to start it. You can take out the pump core, disassemble it and clean it, or replace it with a new pump core without oil.
2. The motor of the yellow oil pump is burnt out, or the motor wire is not connected properly, which causes the yellow oil pump not to start. You can use a multimeter to detect it. The result of the detection is that the motor is burnt out, so you can replace it.