W210 Soft Limp Mode list of causes?

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johnb

Member
Joined
Feb 12, 2006
Messages
57
Hi

I have a S210 320 CDI with ongoing limp problems. All my efforts have been centered on the engine and its various control systems.

It suddenly occurred to me that there must be other triggers for the car going into limp mode while running.

Does anyone know some of the things that can cause 'Soft Limp Mode' e.i. Doesn't record a DTC and can be reset with a restart?

Johnb

Yes I know - 'Get it on Star' :)
 
mine does same , turn off engine restart and ok , till goes into limp mode again
 
Same here

BUT, mine does have a pressure too low fault that kicks in now and then, have checked almost everything, no split hoses I can find, MAF ok, EGR clean, closed and mod done.

Air filter fine, cat seems unblocked. I think either turbo transducer or maybe vacuum tank
 
anyone know of faults that can cause limp mode?
320 cdi I6
 
MAF EGR blocked cats split in a hose could all be culprits, i had a low boost pressure issue on my ML recently and spent days troubleshooting it - although i have a scanner which told me the fault code i still ended up going to a Mercedes Independent and the first thing he did? Put it on Star - the exact issue was diagnosed within the hour and fixed the same day
 
Low battery triggers all kind of fault codes. My battery slowly ran down. My local independent showed me that every fault code was triggered. Only a diagnostic clean down resolved it. Restarting with fresh battery was useless.
 
From recent experience, an independant garage will tend to take ages (and cost a lot of money) diagnosing a fault even before a fix. Take it to a MB specialist or even a genuine MB dealer and ask them to do a star diagnosis and report. They'll give you a printout 5 or 6 + pages long (MB Oxford do a free health check at the same time) which gives you a line by line breakdown of every system in the car and shows you what's working and what's not. They will also reset and clear all the stored codes which can often randomly make things work again!

When you know what's wrong it's easier to fix :) Just don't get disheartened when MB hand you back a quote for fixing your issues which is almost always in 4 figures even for the smallest issue.

Cheers
 
These sure are frustrating cars.
Done pretty much everything i can thing of on this car:
New Air Mass
New Glow plugs - since had 2 fail again
EGR strip and clean - EGR mod fitted
New thermostat
Full service

Just bought Carsoft 7.4 (ideal for these old girls)
Shows glow plug fault (see above)
And boost actuator fault - checked this and it is working fine, no pipe splits, turbo vanes move smoothly, all plumbing as it should be.
Cleared all down and reran the car and now showing air mass fault - which is a new peirburg one. I guess i need to delve further into that one.
 
ml 320 has same problem switch off start with dash lights on press petrol pedal twice then start the engine
 
People are trying to help you here.

You're ignoring them.

Just get it read on Star as many people have said.......
 
i appreciate the help given on the forum here, but to get my car onto Star will cost me £50 each time, I have bought a multiplexer and have a copy of carsoft 7.4, which works very well. This is good enough for this age of vehicle which isn't really OBD2 compliant. It also means that I now can look at the car at my leisure, when I have time to do so.

I live in deepest cornwall, the nearest merc indie is in Plymouth some 25 miles from me, I work long hours 6 days a week, (6.15 - 18.00) so the logistics of getting the car to the garage is not easy - hence my decision to buy the carsoft.

I can now read the DTC's from the car, all I need now is the time and the kind guidance of this forum to try and get my poor old girl healthy again.
 
Hiyer Guys..................johnb is back, with another S210 320 cdi !!

The one that this thread originally related to was sorted eventually, it turned out to be a split in one of the intercooler pipes where it had rubbed up against the chassis, not visible and only found by running the car on a ramp and then running my hand over each boost pipe and joint. As per Dee James's suggestion above.

Here we go again with another W210 320 cdi estate, this one is a 2000 model on an 'X' with 181,000 miles and a full, and upto date, mercedes service history. A huge wad of bills - the last one was £1900 at the end of last year - ouch!

Its going into 'soft limp' as the last car did, I found that the throttle sensor was producing an output of 20% at full throttle, it ramped up from 0% to 100% then fell off a cliff at full depression to give an output of 20%. Sorted that, the throttle cable had been over adjusted.

But the car still goes into 'soft limp' ie restricted to 3k Revs, no faults/malfunctions logged, resets with ignition off. The car will drive quite happily at normal speeds, but if you ask it to pick up a bit it goes into limp.

It has a new air mass sensor (Pierburg), just had full service - oil, and ALL filters, the injectors are all close to each other with their correction factors, leak off test shows nothing amiss. Turbo plumbing all OK! Not being caught by that again!

I don't have STAR (I have other cars so can't justify MB only STAR), but I have been using Carsoft 7.4 and delphi ds150e (good gear) with the correct 38pin adapter.

Open to suggestions guys................
 
Hi - Update

The car is now running mostly as Mercedes intended, EGR mod done, and blocked off for good measure.
Further fiddling got the car to show a P1470, so bought a cheapo chinese vacuum actuator, and all is well.
Still showing P1664 - Electrical heater duff, I will get brave and strip that down at some point hopefully it uses standard glowplugs that can be replaced?

No more limp mode............yippee!

Working my way through various other faults:
1. Driver window slow - fixed with some lub in the motor gearbox and associated runners.
2. N/S/R window does not move, but makes a lovely graunching noise - cable wrapped around the drum (the wrong way) after runner broke up, new regulator on the way.
3. Air con locked out 'RES' button on the climate control, looked at fault codes - 241 'feed me more gas' job done, now working correctly.
4. N/S headlight reflector loose, Xenon lights, going to strip headlight and fix accordingly, probably popped ball joint?
5. Engine was running cool, new thermostat done - much better, now running at just above half marker.

Car going well, just done 150 mile round trip on A roads and dual carriageway and the car averaged 45mpg at an average speed of 58mph - not bad for such a lump. Seems happiest at about 75 - 80 mph cruise.

John
2000 S210 320 cdi Elegance
 

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