EDIT on 10/08/18 = FIXED

Out of the blue, I am dealing with a P0101 (16485) MAF Implausible Signal; Address 01 (first ECM).
I replaced the RH MAF and the 4 pin connector with new; also did the LH side MAF 5 pin connector. Cleared the codes (using a VCDS HEX), buttoned everything back up. Took it for a test drive and pulled:

P0101 (16485) again, Address 01, along with
P0068 (16452) MAP/MAF Throttle position Correlation.
Both times I also pulled - P1857 (18265) Load Signal on Address 02 Auto Trans, but I took both of these faults as a result of the P0101 and not the cause of P0101. Hope I have that theory right.

From this, I am going to now look for grounds (test ground lugs for good grounds), clean TBs, and perform a TB alignment per Ross-Tech.
What I want to know, if anyone has any info:

MAP Part no. - I don't mind replacing these sensors, even if they proved good, as these original sensors are all probably 13 years old.

Is the emission's circuit fused or relayed? I have the E-manual and it is so difficult to use it is almost more harmful than good.

Thanks for any information, or other suggestions. I am capable of some pretty deep diagnostics and I understand these systems pretty well, so I can take in any technical direction or info.

 

Replying to part of my own Qs - I found the MAFS are fused (#5 - 5a) under the cowl in the engine bay, so at least got that far. Now I need to get the cowl removed.

 

My two cents:
The MAF sensor is sensitive, the factory allows an 18% deviation from it's set point. A slight vacuum leak could result in an implausible signal. May I suggest spraying something like starting fluid, lightly, around the top engine area. This could rule out a simple problem before getting complicated.

 

OK, sounds good...on my list.

 

Let me ask a Question:

I'm going back over everything and more looking for an air leak in the intake path. The question I have is about the snorkel tube that attaches to the turbo intake elbow. It is the snorkel that aligns and fits with the rubber gasket on the bottom of the MAF housing. The snorkel feels loose. It seems possible I might have an air ingress at this point, obviously past the MAF measurement.

Back to the question - How does this snorkel fit onto the turbo elbow? How is it sealed? I can wobble it, turn it probably less than a degree or two. Anyone have hands on with removing/replacing this snorkel so I can get mine off, check for a seal?

BTW, one thing I did was to swap the MAFs left to right, etc. Since I am pulling a P0101 on the right side, even with a new MAF replacement, I am swapping, so when I start up I can verify if the P0101 moved over to Address 11. If it stays at address 01, then at least I know I don't have a sensor issue.

 

I was able to get the RS turbo inlet tube off the inlet elbow. Had to improvise on a tool to release the spring clip. I am suspecting a possible air leak here, past the MAF which, obviously would be unregistered air.

Now, I am searching for the O-Ring found on the inlet elbow and mating with the base of this inlet tube. It's approx 60 mm.

Anyone have a p/n or a source for this O-Ring? It should be a replaceable part w/o replacing the entire elbow.

I'm going to remove the LS inlet as well. If I cannot find these O-Rings, I'll try salvaging the old ones. Clean them up and use a heavy coat of dielectric grease.

I DID chase down the MAP p/n = BOSCH 0261230073.




EDIT on 10/08/18 = PROBLEM FIXED