Mass Air Flow Sensor code not the problem

[howardc64]

not sure what a pcv valve is or if its hard to get to??

Turbo charged cars have much more complex PCV system than a simple valve which is why the OP paid over $700 for replacement. Search for PCV in the following link for an explanation on this engine's PCV system and how it works.

https://www.freewebs.com/howardsvolv....htm#487754928

[Voldog]

Somebody told me years ago that a quick way to check a MAF sensor is to start the car, let it run, then pull the sensor connector. If MAF sensor is bad, nothing will happen. If senor is working, something - anything from a stumble to a stall - will happen. I tried it on my '04 tonight just out of curiously and the result was a stumble followed by a rough idle until reconnected when it ran normally again.

Sounds like a logical approach. Am having CEL with MAF sensor code. Read a few posts but looks like MAF may not be the main cause. I'll do this test tomorrow on the car and go from there. Not having any running problems though.

I'll also do this teat outlined howardsvolvo.com:

Boost Circuit
Intake manifold on turbo charged cars switches from vacuum to pressure under boost so can not be used as the exclusive source for vacuum like normally aspirated cars. Instead, the pressure has to be vented to air path between air filter and turbo (just in front of turbo)
I found the best way to do a boost circuit test is to take out the dipstick, stick a tube in it that seals tight against the dipstick tube wall (5mm ID works well). Routed it into the cabin (hood can latch for safety but not fully closed as it will crimp the hose) with a latex glove rubberbanded at the end. Then go for a drive. The glove will inflate because boost circuit is a vent rather than vacuum source. However, one should not get very high pressure. A normal pressure gauge will not even register 0.5PSI. If there is any visible pressure on the pressure gauge, boost circuit is surely clogged. All of this is explained the "Test" section in the following link.
http://www.volvoxc.com/forums/showth...176#post187176
The following link shows a home made device and tested while torquing the brakes (applying both brake + acceleration to create load and therefore boost).
http://www.youtube.com/watch?v=d0SoAjX2xwM
Personally, I like the hose in dipstick tube test outlined above. You can get a better sense beyond just a test for a short few seconds.
Other signs of a plugged PCV is the dip stick being forced out of its hole and oil leaks that aren't the common ones (turbo return line, oil filler gasket) This is because the engine chamber where the oil is should have negative pressure (caused by PCV system) If the PCV system is clogged and there is positive pressure present in the oil chambers in the engine, there is force to push out the seals and cause leaks.