So, I took my 05 E320 CDI in to the dealer today (still under warranty for another few miles) because of an intermittent loss of power.

On two separate instances in the past 2 weeks the car has been only minimally responsive to throttle inputs. The car will accelerate, albeit very slowly, and shifts through the gears as normal, but there's no power, and it won't downshift even if the kickdown threshold on the accelerator pedal is pushed.

1st time it happened I had been driving for about 5 minutes, and it occured once i stopped at a light and then pulled away. Shifted all the way to 5th gear, but had no power all the way to 45 mph.

2nd time it occured, I had been driving for about 30 minutes, I was on the interstate doing about 80 mph, and went to change lanes, and had no power. Wouldn't downshift, same as the last time.

Both times, turning the car off and back on again made the problem go away.

I did some searching, and it sounds like the typical EGR valve issue that these cars face. I haven't had it since new so I don't know if it's had the revised EGR and reflash or not. I'll call the dealer tomorrow and see if they can look it up.

The dealer didn't seem conviced by my EGR theory, and ran the codes and came up with an O2 sensor and MAF code. Didn't have any light on or messages in the instrument cluster, so I guess they must have been stored in the computer.

Considering it would shift through all the gears, I believe that eliminates the 2nd gear only limp home mode.

Anyone got any other theories??????

Will

 

It does sound like the EGR issue.

 

When I told my dealer that my EGR was acting up they looked at me like I had just said health care reform would pass within a month They claim they had never known of such an issue and wouldn't be able to diagnose anything without a code (lazy IMO) and the EGR wasn't throwing any codes.

I'd say that it is more than likely the EGR in your case.

FWIW I had this issue constantly when I first bought the car, I changed where I buy my diesel (probably a red herring) and changed my driving habits. I use to drive like little ole granny anytime I took this car out, now I give it the goose once a drive, blow everything out the tailpipe. Haven't had a single EGR issue since I started driving like a power hungry teenager

 

So I picked it up today (could not duplicate the problem at the dealer), got about 2 miles from the dealer and it started doing it again. Took it back and they hooked it up to the computers without me turning it off, and the MAF readings were way out of whack. I left the car and they said it should be ready to pick up on Friday. Fingers crossed that this does it and no more problems.

As for driving it like a power hungry teenager, that's what my dealer told me to do also. To blow the crap out of the engine. To which I replied, "okay.!!!!!"

 

Unfortunately it seems that many dealers do not see their share of CDI vehicles in for service on a regular basis, and they are many times misdiagnosed if a DTB is not available. And in some cases, even if it is available they can still not be repaired properly.

I had my experience with the EGR issue and my symptoms were the exact same as yours. I noticed a power loss while driving at normal speeds. When climbing a hill, it becomes very apparent that something is wrong - no power, no automatic downshift and no turbo power. A simple stop and restart of the engine would cure the problem, but I drove 30+ miles one day with it that way and it was pretty apparent it was not going to resolve itself without turned the engine off.

Also, another symptom was a surging of the engine. While driving at a constant speed (typically in a lower gear under very light acceleration) the engine would surge - it could be felt and also noticed on the tachometer. This happened pretty much 100% of the time in the same areas in my daily commute - one place I really noticed was when the car was still relatively cold and I was leaving my driveway which has a downhill slope, the car would jerk when it was under a very light load. This was sporadic in the beginning but only got worse as time went on.

If you do indeed have the EGR problem, I feel sure that you will encounter similar symptoms as above, and they will get worse. I hope they are correct in diagnosing your car correctly, but it does indeed sound like an EGR issue to me.

My dealer was hesitant the first time however after running the codes myself and matching them to the DTB, I took a copy of the DTB in and said "here - fix this" and they did. They also never put the correct amount of oil (!) in my car. It is always too full or too low. Again - I don't think they get many CDIs in and they put in the same amount as they do a gas motor.

Good luck with the repair.

 

Well, I'm hoping that the MAF fixes the problem for good. If not then hopefully the EGR rears its head again prior to my newly extended 90 day warranty.

I too haven't had the best luck with finding intelligent dealer service departments. I'm an avid enthusiast and typically find myself having to assist in the diagnosees of issues on the various vehicles that I've owned. I've even been offered jobs by 2 different service managers. Which I find a little sad. I don't think I'll quit my day job anytime soon though.

Hopefully this one is getting it sorted right though.

 

Yeah, get it taken care of before your warranty expires, mine is out of warranty and if the EGR problem does come back I'm looking at $700 to remedy (indie shop can't do it as it requires a CPU flash, so dealer only). Good luck, but I doubt it is the MAF

 

Well, I finally got it her back yesterday. The dealer decided to goa ahead and replace the MAF and the EGR, and do the reflash, and while he was at it he swapped out my rearview mirror with one that they were sending off to auction (my homelink didn't work), so now everything works as it should. :-) Sweet.

Every time I drive this car I love it more and more. Got to love the Benz's. Fingers crossed for no more issues.

 

Let us know how it works out.