I have been struggling trying to resolve a P000A code for several months on a 2007 A4 2.0L. In order to resolve this I have replace the N205 Cam Position Sensor, replace the timing belt, verified there are no blockages in the oil pickup or anomalous oil pressure, and examined the Camshaft. I've taken it to two trusted import mechanics both recommended in the end taking it to Audi since they could determine nothing causing the error.

Audi service inspected the car today and determine that there is evidence of oil migration into the engine wiring harness where oil seeped out of the old defective N205 Cam position sensor.

Estimate to repair the issue from Audi USA $3500 - new harness, N205, and 2 power relays including 11-14 hours of labor.

The car has 150K miles and I can't see spending this much money on it. I'm discussing the possibility of trying to resolve this issue by tracing back the fault in the harness and splicing as appropriate with one of my mechanics or acquiring a tested used harness and possibly replacing this myself.

Other thoughts?

Can oil really be the culprit seeping into the harness and can it really take 14 hours to replace the harness?

 

I'd see if I could find a used harness and replace the oil soaked portion like you mention. I'd definitely solder and use heat shrink on any connections.

I've not heard of oil causing wiring issues though. I guess it is possible if the insulation is not oil resistant. But you'd figure that auto manufactures would use an oil resistant insulated wire, no? It also possible that oil has soaked into various connectors which can lead to electrical bridging between circuits... I good cleaning with a degreaser might fix that.

 

I took a closer look at the wiring can't see how oil could get past the point where the two cam position sensor wires join back into the main harness and the covering is cracked around that point as well. So I used a hexane based electrical contact and grease cleaner to spray from the crack out to the connect cleaned out any contaminants. Cleaned the connector and the N205 (cam position sensor).

Waited for everything to dry.
Reset codes which had been returning P0001 for the past few months.

Ran car now new code P0011. Are these codes? related what should I pursue next?

 

P0011 is also a Cam Shaft Sensor Code. It means it's sensing the cam timing is over advanced. How did the car run when you fired it up?

 

It idles just a slightly rough. Acceleration and normal driving are all fine,

 

Has the timing belt been changed on this engine recently? I had a similar issue with a Mitsubishi Eclipse that I changed a timing belt on and it had a slight lope at idle. Ran and accelerated fine. Turns out I had the timing off by one tooth. Not enough to cause any valve damage but enough to mess up the idle. I wouldn't have been so mad at myself if it hadn't been for the fact that I set the timing (new belt) with the engine OUT of the car (changing the clutch). Had to fix it with the engine in the car the second time. It wasn't too hard to do but.... DOH!!

I've not worked on any of the 4 cylinder Audi's yet so I'm not familiar with the specifics but all basic timing principles apply on most of the newer 4 cylinder, 16 valve engines. See if you can check the timing of the belt. It's possible one or both of the cams might be off a tooth which would lead the computer to believe there is too much advance on the timing.