2005 E320CDI Code Set
 

"Supercharger/Turbocharger Overboost Condition". Car is performing perfectly otherwise and has 168,000 miles. Please advise.

I cleared the code and it reset after a couple of days. This was during very easy driving at less than 50 MPH. As the car is never pushed very much, I wonder if a pressure sensor might be failing, or the wastegate may be sticking? After all, it is 12 years and 168000 miles old.

Anything?

If the true problem is overpressure (vice a bad sensor), perhaps it is related a faulty pressure relief valve, allowing overboost?
Since the car's performance is unrestrained, it suggests you are getting (at least) full expected pressure in the intake.

If it were me, I'd be rigging in a pressure gage on the boost side to verify actual manifold pressure.

Jim

Think I got it: looked at the snapshot ofvthe operating parameters saved when the code was set and all looked normal but the manifold pressure reading at just over 12,000 PSI. I call a faulty manifold pressure sensor.

Randy, is the pressure really 12,000 psi? That strikes me as unbelievably high. You have a pressure gauge that reads that high? What material is the manifold?

No, of course not. Any time a code is set the OBD system records a snapshot of engine parameters. When this code set, it recorded the boost pressure in excess of 12,000 psi, which is obviously impossible and therefore a failing pressure sensor. I have a new one ordered.
Meanwhile after clearing this latest code I completed a round trip of almost 700 miles this weekend, and NO CODE. I am still changing the boost pressure sensor.