Altitude / Ambient Pressure Sensor Location?

Is this located in the ecu? Also would this be a plug a play item? Thanks.

It is in the ECU.
What would be Plug and Play?

I should say remove and replace. Vag not necessary? Exactley where is the ecu located?

What problems are you having that are related to the ambient pressure sensor in the ECU?

I have been trying to solve the hesitation issue since 22000 miles when the surge, hesitation started. I now have 89000 miles on the car. I have been to four dealers, two in Phoenix, one in Flagstaff and one Bellingham, with the same results. No light no fix. I am unable to duplicate the occurence, but it only happens when oat temps reach 55 degrees plus and at altitudes of 5000 feet or more. Also, I noticed no hesitation at speeds of 75mph or more.It does not happen at sea level or there about. The hesitation is random in nature, seems to have a mind of it own. That is why it is difficult to reproduce. While talking with a Porsche mech he suggested the altitude sensor may be an issue. The part was cheap enough to give it a try.

quigley said:

The part was cheap enough to give it a try.

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I did not know they sell ECU parts separately. What was the part number?

I gather if I had a bad altitude sensor I would get a light of some sort and would have to replace the ecu. Is that correct? The part I have is a boost pressure sensor. 0 281 002 399. I explained when ordering that I wanted to replace the altitude sensor, and this is what I got. Live and learn.

At startup, the ECU compares the pressure reading from itself and the MAP sensor, if the two differ too much, you'll get a CEL.

I guess we first need to verify everything is working as it should. Got access to VAG-COM/VCDS?

I do not have access to VAG. I live in a remote area of northern AZ. I don't know if anyone in Phoenix has one. Since I do not have a CEL what should I assume could be causing the problem? I did have the Flagstaff VW dealer check the system via VAG with no negative results. From reading the forums the 06 is a hardware issue unlike the 09 and 10. Others on this forum have reported hesitation issues, but I can find no fix. Thanks.

Rereading the threads on MAF I decided to disconnect it. Two days and 220 miles later the hesitation has not returned. Could it be so simple?

quigley said:

Rereading the threads on MAF I decided to disconnect it. Two days and 220 miles later the hesitation has not returned. Could it be so simple?

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Could be, sometimes MAF issues are intermittent and don't trigger a DTC/CEL until they get really bad.

Swap in a new MAF and see how does.

Installed a new MAF. After 9 starts the CEL went out. The next day when I started the CEL returned and will not go out. Does this change require a VAG to extinguish the CEL? I have disconnected the MAF harness in the past with the CEL extinguishing after a few starts.