2005 E320CDI Post-Water-Pump Code
 

Hi, just finished changing the water pump, belt, idlers, tensioner, and hoses. Also replaced the manifold pressure sensor (again). When I started the engine for post-repair checks, I found CHECK ENGINE illuminated. Whipped out the trusty OBD II scanner and found 1 code: P0069 manifold absolute pressure barometric pressure correlation.
I erased the code but it resets as soon as the key is on and before the engine starts.
I had to remove the air filter box and turbo inlet elbow duct and unplug the involved harness to change the water pump so I figured one of these is not making contact. I checked and they appear to be fine. Can anyone guide me here?
Water pump and associated repairs seem fine btw.

Is the hose connected to the MAP sensor? Maybe the hose is degraded.

Sixto
98 E320 sedan and wagon

Hose is connected and seems in fine condition. Also, as the code sets before the engine is started, I suspect harness/connector/ end device issue.

Recall that I changed the manifold pressore sensor. Perhaps the replacement sensor is wrong?

How long ago was the MAP sensor replaced? If it's been working before your water pump R&R, it's highly doubtful that it's the wrong part since you'd have had codes long before now.

Sensor failed about 1 1/2 years ago so I replaced it. Failed again a couple weeks ago. I noticed the new one I installed (ordered fromPeach) was USA-made and had 1 digit different from the one I removed (Bosch). I think I have the wrong part.

Did it work after you replaced it though? Or is the light a recurring problem ever since replacing it? I ask because you may not have a sensor problem, you may have a wiring problem...

No, it has never worked; I replaced a failed sensor while I was replacing the water pump. I am convinced I got a sensor for a gasoline car by mistake so I have ordered another.