This kind of sensors often do not go broken completely. They work, stop working, work again, depending on temperature or any other kind of environmental condition. So it was not the amount of oil added but the fact that you have waited some amount of time that made the sensor work again. The camshaft sensor sensor should be exchanged as the faults it produces will increase over time. Before doing so, check the cabling and rerpair it if needed. But in most cases, simply the sensor is the problem. It is very uncommon that these sensors break down in a Toyota from the nineties, so I never needed to exchange it. To my knowledge, it should be placed in the distributor.