How high is your oil level? If it's less than 1/2 between the two marks, it will trip the sensor in my experience. Sensors also can go bad, although not common.
For the light warning, do you have DRLs? The current difference with HIDs trips the sensor. If so, just order a US headlight relay and replace yours. It will trick the system into thinking your lights are fine.
For your ABS, does the system still work? The relay has a notoriously brittle connection in it, causes 90% of E30 abs problems.