jtjgvle

I posted this in the X164 section before realizing there's a dedicated diesel section.

2008 GL320 approx. 155K miles

I've got symptoms that seem to fit a swirl flap issue (sudden loss of power, even with pedal to the floor that goes and comes) but the codes I'm getting don't seem to point right to that, any ideas or advice on how to eliminate possibilities? Here are the codes I'm getting from my iCarsoft MB2 scanner:

2359-1 Current Check system "charge Pressure Control" too low boost pressure.
2601-2 Historic Mass air flow sensor right the air mass is too small.
2355-2 Current Check system "Exhaust gas recirculation control" the air mass is too large.
3053-1 Current Check component B2/7b1(intake air temperature sensor) The signal voltage is too high

Cleared those codes and 2355-2 and 3053-1 came right back.

Additional information, about a year ago I replaced the turbo actuator and about two months ago I replaced the MAF sensors/intake air duct assembly because it had cracked at the turbo connection.

kajtek1

You have several different codes. Did they come all together? In such case I would suspect dirty plug, or other connection problems as things don't break in 4 at the same time.
If they accumulated 1 by 1 over the time, you might have multiple sensor failures.
In such case I always start with the most obvious and/or cheaper issue to solve.
Also I had several issue with MB2 scanner giving me bogus data. Your "coming right back" codes would indicate that.
Whenever you clear the codes, restart the scanner by cycling the ignition and scanner and confirm it did actually clear them.
Sensor errors should not come back unless you run the engine.

jtjgvle

Thanks for the reply! I wasn't very clear in my original post. I meant those two codes came back after I drove the car around the neighborhood. I did confirm all the codes were cleared before I did that.

B34chBum

First thing to check is the connections and condition of the boost hoses.
The hot-side hose may be split at the lowest turn, before coming away from the motor on the way to the intercooler.

tjts1

You have a boost leak.

John CC

The two codes that came back would seem to indicate your EGR valve is stuck or won't close properly. To much airflow and to hot.

Plutoe

i think your something is just that until you look at the function and wiring diagrams for your VIN----all else is a great circle conversation

hai00

*** Your issue may be covered under Mercedes diesel settlement in North America. MAF sensor and EGR valve. ***

Your codes seem to be related to parts that commonly needed to be replace in OM642.
Here's what I see from personal experiences:
- Mass Air flow sensor fault: MAF fault usually doesn't cause OM642 to go into "limp mode" (lost of power, even at full throttle). If you have not replaced it within last 40K miles or so, it could be faulty. You could try to take it out and clean it with spay can, it but unlikely to fix. Be very careful with the rubber gaskets if you do. Those get damage easily. All connection should slide in easily. If you have to use a lot of force, then something is wrong, and you likely will pinch the gasket, needing gasket replacement later. If you go DIY route, there is new, and remanufacture. New is around $1000, reman is around $600. Again, this should be covered by Mercedes settlement warranty

- EGR fault: This will cause engine to go into limp mode. You can try to clean it or replace. If you have not replace it recently, may as well replace it. Not so easy on yours, but do-able. This is an expensive repair too. Again, this should be covered by Mercedes settlement warranty

I had both of these issues concurrently 2 years after AEM recall. Took dealer a few times, each visit lasted around 1 week, to fix all because these kind of warranty repairs earn dealer less money. Sometime they would come up with reasons why something is not covered. If you are still covered by the AEM recall, please play nice with dealer and they should fix them.

jtjgvle

For anyone that was interested, after several weekends of tracking down everything that should have been related to these codes, on a whim I took off the MAF air duct assembly I had replaced about 6 months ago and stuck the old one back on (glad I kept it) and problem solved. I had only replaced it because of the common issue where it cracks at the turbo attachment. I think I'm going to get one of those silicone repair pieces and stick with the old part.