hoseclamp

Having issues here, seems to be occurring the same way. Wife is driving, slows to make right turn, down to 20-30kmh, gets back on throttle and no power. Like only 5% of the pedal stroke is only active. Will eventually get to speed but does not clear unless vehicle is shut off and restarted. No codes ever show up and it doesn't go away on its own. Luckily it doesn't occur when on the throttle making passing an issue. It always seems to be slowing, making a turn and back on it. Has 19,000kms, just over one year old. Didn't do it until the spring of this year. Thoughts?

PeterUbers

That's scary... Has dealership been able to replicate this problem yet? I would think that resetting the adaptations may be of some benefit but I'm not sure please keep us posted

hoseclamp

Dealer has not seen the vehicle since I purchased it. We are 550 miles up north from it. We have been discussing and trying to diagnose through trial and error. My mechanics have been chasing the ghost with thier direction. Will definitely keep you posted.

eric.gray

We have 2 issues that have occurred with our 350:
1 - similar in that near complete loss of power. You press on the peddle and you get 10 - 15 percent of power or so. If does eventually go back to normal.

2 - other is worse. She's pulled up to a light of stop sign then presses on the accelerator and NOTHING. Try paddle shifters, put in park and then drive .. nothing. Turn it off, back on back to normal.

We took it to the dealer for #2 and they could find no codes or issues, #1 just started in the last week. If you find a fix or the dealer, would love to hear it. Love this vehicle but not acceptable for a $70K+.

hoseclamp

We just did our fall service. Check all fluids filters change engine oil filter winter tires wheels etc, one of my mechs thinks a few sensor plugs on drivers side intake was not connected 100%, which could create a fluctuation in voltage through it and resulting in issues. Talked to dealer service working on issue about it. All is snug now, we wait and see if it occurs again. If we go a month it's cured. Never been able to go that long since spring service. At the most a few weeks.

Eric, when issue #1 occurred in your '11, how long does it take to correct, I drove our '14 for over half hour with no change unless we shut off and restart. Never had issue #2

hoseclamp

To follow up, after service and everything connected right, no further issues. Side note one of the washer jets broke, had to cut it out of line so we only have three jets now, had to cut washer fluid heater line, doesn't matter we use -40c fluid anyway. We get fixed in spring when I take it down. All else good.

N_Jay

Check out the W164 and X164 forums. Lots of issues with going into limp mode.


Current thought is it is usually it is the DPF differential pressure sensor.

hoseclamp

I'll check it out. Thx!

hoseclamp

Well it's been a lot of hit and miss, the poor power cleared up, was good for 7-8 months, came back late summer, finally got a check engine light and code.


P0471 Exhaust pressure sensor A Circuit range/performance.


Sent that info to the dealer since I already had an appointment for it and maybe chasing down the issue, now we know what it is. It's erratic, no pattern, and even after a few starts it cleared itself. Hopefully it will be good to go a year at time up north without any other issues.... finally found the ghost in this thing.

hoseclamp

Final update, sensor changed on exhaust emission side, few small decor warranty items, all is running great. No issues.

hoseclamp

It's back, anyone else had this issue? Any resolution besides trading for a gasser?

N_Jay

Are you saying the problem is back after changing the exhaust differential pressure sensor?

hoseclamp

Hello! Yes it's back, we are back down south in Kelowna, dealership has been all through the rig, it only comes once a year, full scope front to back, same with my s class, once a year checkup, we do servicing up north. Found a few things off, one sensor on the turbo end not communicating, makes sense. A broken transmission mount, leaking transfer case, 43,000 miles, not bad considering 3 years old this September. Loves to chew through tires, didn't get two summers out of the Pirelli zero's, these conti's aren't faring much better. Everything else holding up great.


If it isn't fixed for good, have already discussed buy back options, wouldn't be a big deal if we lived in town with in town speeds, but when this thing won't accelerate, you only find out once pulled out on the highway, a 70mph zone, and there's 62,000kg rigs out there steady on this section of highway. It isn't being reckless, you have about 20 seconds of clear highway on one side, and 30 seconds on the other, we are at the bottom of the valley so you're accelerating up hill both ways. The only way to clear the issue, you stop, put in park, turn off, open/close door, start, in gear and go. That isn't enough time, and when the road is ice and snow 6 months of the year, you don't have the room. This is a mortality question, they're taking it back if it happens again. Lucky for me, I have a great dealership to work with, they are not opposing this at all.


To be honest, I'm a bit disappointed they found the possible source of issue, there's a beautiful white '17 GLS63 with 22's I was ready to take home


Hoping all is fixed, as much as a new rig would be great, but the wife wants diesel, loves the mpg and green carbon footprint, it is her suv, I rarely drive it.

hoseclamp

So far so good.......would be great if the wife uses the mirrors or sensors/warning system to tell her she's backing into a fkn fence.

hoseclamp

Power loss is back. Not letting my family ride in it anymore. Told dealership it's coming back, will be talking to MB on this one.

N_Jay

With all the computers in a MB, I am surprised that they don't just have a data logger to install and let run.

f4i 954

there as been several problems like this and the correct fix for all the ones i have seen was to replace the pins at the cdi control unit for the exhaust back pressure sensor, most of the time there is no faults but under faults with no filter there is faults for exhaust back pressure sensor

N_Jay

Makes some sense.

Since it is a piezo sensor the signals are very small.

I suspected it was as much a connector getting wet issue as a bad sensor. Could be at the other end of the wires at the controller.

f4i 954

i have seen sensors and connectors at the sensor replaced several times but they all came back for loose pins at the cdi. There is 2 types off sensors, the only way to tell them apart is by scent hole in the sensor.
a unplugged sensor will give a default value which is what the loose pin at cdi will do causing it to go in limp mode, vey little or no boost, very slow upshifts and desabling shift paddles

N_Jay

Every time mine acted up was in wet weather below freezing.
Being an 2008, my sensor is underneath and open to road spray, not on the firewall like later GL diesels.

The limp mode is very noticeable as boost is gone and shifts happen very early to keep revs down.

The shift paddles work, but only within the RPM range allowed in limp.

hoseclamp

They've done this exact repair, went quite a while since the last time it acted up. Traded today, pricey remedy but problem solved. '17 GLS450, black ext tobacco interior.

joeboch348

Today my 12 gl350 lost power. I thought the turbo went. In neutral it wont go past 2500 rpm. Any ideas.