Oil leak

I cannot think of any oil lines up there. But are you sure it is oil and not power steering fluid? They can kind of look the same and be confused easily. And if it was leaking from the reservoir it could easily ride along with the belt around to the alternator, water pump, and A/C compressor.

Highly doubtful that it had manage to come out there and get up that high. The only oil seal up there is the front main seal, and it would not have the pressure to blow out like that. It would be seeping out and going down the front of the engine. But the power steering system has pressurized lines up there. A pinhole leak could shoot power steering oil a good distance and definitely get it up there.

Definitely. First start the car and raise the hood. Poke around with a flashlight and see what you can see. When you see where it is coming from, take a picture or two and we will try to identify exactly what it is.

Check the level of power steering fluid and engine oil.

Get some engine degreaser and spray it all around there. They have got instructions on the can, just make sure not to spray any electrical connectors. Then see if it comes back. To me that looks like just years of gunk and grime building up. It could be a leak of some sort, but I am not sold on it being a leak. Do go ahead and check all of your fluids, so if one is leaking you will know for sure.

If it is engine oil, it is probably from old dried out valve cover gaskets. A common issue on these cars. That is a common issue on all cars. It would be a slow leak, that runs down the front and/or side(s) of the engine.

See what you find.

If the gaskets have already been replaced, then that is probably just old crud that was not cleaned up. Still a good idea to degrease it and see if there is a leak there. If there is a valve cover gasket leak, it would probably just mean that the bolts need re-tightening.

P0405 is saying that the signal voltage coming back from the EGR pintle position sensor is too low (possibly 0).

The way it works, simplified, is that the power-train control module (computer) supplies a twelve volt lead voltage to the sensor. The voltage goes through the sensor, and depending on the position of the sensor, returns a signal voltage. When that signal voltage is consistently less than 0.14 volts, the code sets.

Most likely causes are going to be (1) a failed sensor, (2) no reference voltage from the PCM (basically the lead wire is broken/shorted/screwed up at the connector) or (3) The ground wire is weak.

Basically, you need to make sure that you have twelve volts coming from the PCM and that the ground wire is good. If those are good, then most likely your issue is the pintle position sensor (built in to the EGR), which would not be terribly surprising if it is an aftermarket EGR valve.

You can also check the signal voltage going back if you can get a lead from your multimeter into that wire.

Okay, it is really not hard to actually test. Just sounds difficult. If you have a $10.00 multi-meter, you can do all of that testing. Or you can pay someone $80.00 to do it.

Regarding the P0410 - Check #35 in the images below. It is the relay for the air pump. You can buy a relay for a few bucks and try it. Cannot hurt.