E36 M3 Oil warning light

Hi, I'm new to these forums. I have a 1998 E36 M3 4 door. Recently when I start her the oil light at the bottom below the speedo blinks 9 times in red and then goes off. The same thing happens when I turn the ignition to position 2 without starting the vehicle.
The light does not come on while I drive only at start up. Could anybody offer me some advice as to what the cause could be or a remedy?

Many Thanks