If your vehicle is showing low oil pressure warning light illuminated, here are the most likely causes and the parts you'll need to fix each one.
The engine does not have enough oil to maintain proper pressure, usually due to oil consumption, burning, or external leaks.
The sensor that measures oil pressure has failed, become clogged, or is leaking, triggering a false warning light on the dashboard despite normal actual pressure.
A heavily degraded oil filter restricts flow. Alternatively, a recent oil change error (like leaving the old filter gasket stuck to the block, causing a 'double gasket' leak) drops pressure rapidly.
Using the wrong oil weight or heavily degraded, fuel-diluted oil that has thinned out can cause pressure to drop, especially when the engine is hot.
The mechanical pump responsible for circulating oil is wearing out or failing, leading to a genuine and dangerous loss of oil pressure.
Excessive wear on internal engine bearings (main or rod bearings) creates too much clearance, allowing oil to escape faster than the pump can supply it, dropping overall system pressure.