Limp home mode when accelerating. W211 E270 Cdi 2004

[james2747]

The car has covered 118,000 miles.
I have had this problem for well over a year ... and can't find out what is causing it.
Just normal 'quick' use of accelerator, as when overtaking someone, frequently results in the car going in to 'Limp Home' mode.
I'm not slamming accelerator to floor, just reasonable use of accelerator for example when accelerating to overtake another car.
It also doesn't occur every time but when it does, I have to find a safe place to pull over, switch off ignition .... immediately turn back on again and all is well ... limp home mode has gone.
It does occur every time ... if I test it out on a quiet road and push accelerator hard to the floor.
There are no fault codes, I do have an iCarsoft i980 code reader.
I've checked turbo shaft play .... virtually nil.
Engine crankcase breather renewed ... no difference, problem continued.
Have checked all vacuum pipes and connections (twice) and found them all to be sound and pipes not cracked but in good 'flexible' condition.
Engine is in good condition, returns over 45 m.p.g. on a run and oil and filter changed every 8,000 miles.
Any help, pointing me where to look for the cause of this annoying fault would be very much appreciated.

 

[MJJ]

I cannot offer an immediate fix, but if it were me, I would be using the Live Data function of CarSoft to try and pinpoint which sensor is going outside of tolerance and thus causing limp mode. Monitor these when accelerating below limp mode trigger, then compare to above limp mode trigger.

Appreciate that the lack of stored fault codes is annoying, but the fact that an ignition reset fixes the issue very strongly suggests something sensor based rather than mechanical.

I would be focussing on the sensor inputs that are most likely to be part of engine protection strategies in the ECU, so boost level, intake charge and exhaust gas temps, coolant temp, and any cylinder misfire PIDs.

Martin.

 

[V6Matty]

I had something very similar in my old 211, it was an O2 sensor in the inlet I believe that was out of range, however I did have a stored code about boost pressure too high I think (this was about 6 years ago now) so I had something to look at but as above the code just lead us to checking live values to find which component was out of range.

just worth noting too that the 211 got the OM647 rather then the OM612, so everything is electronic rather than vacuum operated in the engine,

 

[Chrisbart]

I had this problem on my old 211...turned out that there was a tiny split in the boost pressure hose...swapped it for a new hose and problem solved.

 

[trampo88]

I had the exact same problem on my ML - drove me nuts. I know this answer is about as useful as stevie wonder's sunglasses, but it was some actuator pre or post the turbo - a local auto gearbox specialist (I know, sounds unlikely) I had used before had heard of the problem, and solved it with an aftermarket or recon part for about 200 quid. Apparently MB would have wanted to change the whole turbo so saved me a packet and my sanity. Also the fault codes didn't point to it in that case either. I feel for you - hope you sort it!

 

[abazem]

I had the same symptoms couple of years ago and it turn out the actuator on turbo was sticking (as described by trampo88 above). I would suggest that you plug it to Star to read out the fault code and take it from there. It could be many things and you'll keep guessing until you put it on Star.

 

[mioba]

Turbo actauators dont throw up codes. They fail on laters models primarily the OM642. Had this on my W251. Mage sure you mathc the numbers on the actuators as they are specific. If you are not using the car much many places repair the actuators.
Make sure the arm is moving freely, give it a spray with oil.
The plastic worm gear wears out and the solders can crack as its near a hot turbo

 

[trampo88]

Turbo actauators dont throw up codes. They fail on laters models primarily the OM642. Had this on my W251. Mage sure you mathc the numbers on the actuators as they are specific. If you are not using the car much many places repair the actuators.
Make sure the arm is moving freely, give it a spray with oil.
The plastic worm gear wears out and the solders can crack as its near a hot turbo

I think that's the engine I had (3.0 V6 2008 W164) - the worm gear drive being worn rings a bell. I recall it was something pretty lo- tech that was causing the problem. It ran like a dream after, or least as well as 2 ton of german tank can do!

 

[mioba]

and yes, as noted above, MB dont sell the actuator sperately, so whip it off if you go that route and get it seperately if you go that route.

Yes common issue on the ML and R

 

[rf065]

Had the same problem on my CLK, split intercooler hose was the culprit.

 

[00slk]

My pick would be the intercooler pipe, I have a car coming to me shortly with the same symptoms, split pipe most likely problem as they are working fine with not too pressure at normal driving but give it some welly and the pressure came open the split which can sometimes throw it into limp mode.
If you stop the car and switch off as soon as this happens, and restart does it still have limp mode?

 

[james2747]

I cannot offer an immediate fix, but if it were me, I would be using the Live Data function of CarSoft to try and pinpoint which sensor is going outside of tolerance and thus causing limp mode. Monitor these when accelerating below limp mode trigger, then compare to above limp mode trigger.

Appreciate that the lack of stored fault codes is annoying, but the fact that an ignition reset fixes the issue very strongly suggests something sensor based rather than mechanical.

I would be focussing on the sensor inputs that are most likely to be part of engine protection strategies in the ECU, so boost level, intake charge and exhaust gas temps, coolant temp, and any cylinder misfire PIDs.

Martin.

Thanks MJJ
The sensors that protect the engine make sense. It points me in a few specific areas to investigate.
Your reply much appreciated.

 

[james2747]

I had something very similar in my old 211, it was an O2 sensor in the inlet I believe that was out of range, however I did have a stored code about boost pressure too high I think (this was about 6 years ago now) so I had something to look at but as above the code just lead us to checking live values to find which component was out of range.

just worth noting too that the 211 got the OM647 rather then the OM612, so everything is electronic rather than vacuum operated in the engine,

Thanks V6Matty
I'll see if I can get any errors showing up on O2 sensor and also check my boost pressure using iCarSoft meter.

 

[james2747]

I had this problem on my old 211...turned out that there was a tiny split in the boost pressure hose...swapped it for a new hose and problem solved.

Thanks Chrisbart
I have checked hoses for splits a few weeks ago ... but as you mentioned you found a "tiny split" in yours I'll double check mine again.
Thanks for your response.

 

[james2747]

I had the exact same problem on my ML - drove me nuts. I know this answer is about as useful as stevie wonder's sunglasses, but it was some actuator pre or post the turbo - a local auto gearbox specialist (I know, sounds unlikely) I had used before had heard of the problem, and solved it with an aftermarket or recon part for about 200 quid. Apparently MB would have wanted to change the whole turbo so saved me a packet and my sanity. Also the fault codes didn't point to it in that case either. I feel for you - hope you sort it!

Hi Trampo88
Thank you for your response ... I'll have a check as to what sensors or actuators live pre and post turbo, to see if I can find any that are causing me the problem.

 

[james2747]

Turbo actauators dont throw up codes. They fail on laters models primarily the OM642. Had this on my W251. Mage sure you mathc the numbers on the actuators as they are specific. If you are not using the car much many places repair the actuators.
Make sure the arm is moving freely, give it a spray with oil.
The plastic worm gear wears out and the solders can crack as its near a hot turbo

Hi Mioba
I hadn't checked out the actuator as everything runs fine normally so I assumed actuator must be operating ... but I will definitely give it a close examination now you have mentioned it as a potential cause of my problem.
Thanks very much for your response.

 

[james2747]

Had the same problem on my CLK, split intercooler hose was the culprit.

Hi rf065
Have recently checked this but will definitely do another very detailed check of the intercooler hose.
Thanks for your response.

 

[james2747]

My pick would be the intercooler pipe, I have a car coming to me shortly with the same symptoms, split pipe most likely problem as they are working fine with not too pressure at normal driving but give it some welly and the pressure came open the split which can sometimes throw it into limp mode.
If you stop the car and switch off as soon as this happens, and restart does it still have limp mode?

Hello
00slk
Your response much appreciated. I have recently checked this but your logic is very sound regarding it 'leaking' when under boost.
So will now do a really close inspection.
Yes. limp home mode always disappears when I switch off and switch on again.

 

[00slk]

Hello
00slk
Your response much appreciated. I have recently checked this but your logic is very sound regarding it 'leaking' when under boost.
So will now do a really close inspection.
Yes. limp home mode always disappears when I switch off and switch on again.

Fingers crossed for you.......It is quite difficult to find a split hose as they are fairly robust. Hopefully it will be a cheap fix?

 

[philreed52]

The car has covered 118,000 miles.
I have had this problem for well over a year ... and can't find out what is causing it.
Just normal 'quick' use of accelerator, as when overtaking someone, frequently results in the car going in to 'Limp Home' mode.
I'm not slamming accelerator to floor, just reasonable use of accelerator for example when accelerating to overtake another car.
It also doesn't occur every time but when it does, I have to find a safe place to pull over, switch off ignition .... immediately turn back on again and all is well ... limp home mode has gone.
It does occur every time ... if I test it out on a quiet road and push accelerator hard to the floor.
There are no fault codes, I do have an iCarsoft i980 code reader.
I've checked turbo shaft play .... virtually nil.
Engine crankcase breather renewed ... no difference, problem continued.
Have checked all vacuum pipes and connections (twice) and found them all to be sound and pipes not cracked but in good 'flexible' condition.
Engine is in good condition, returns over 45 m.p.g. on a run and oil and filter changed every 8,000 miles.
Any help, pointing me where to look for the cause of this annoying fault would be very much appreciated.

Had same fault with my 270clk 2005 mine stalled on hard acceleration pull over restart as if nothing was wrong sometimes EML and limp mode . Took to my local garage no faults took for second opinion to MB specialist no faults but he thought could be bad fuel as filled up at Tescos.
Have put bottle of redex to £30 diesel (Branded not supermarket) a few time and no EML and turbo all the time . I also changed fuel filter twice . Running well for last 4 months .


Sent from my SM-G781B using Tapatalk