W211 220CDi Limp Home

[Mr E]

Had a pants journey into the office this morning when the car switched into "limp home" mode (lack of power, limited revs, etc). Turned it off, restarted, draopped back into limp home after 100m.

Mobilio came out to the office - Error 0202 registered (low boost). The guy cleared the code and a test drive didn't reproduce the problem.

The question is that I had to follow a nasty truck chucking out oily gunk from it's rear end - the front of the car looks pretty grotty and it's a nasty, oily residue. The drop into "limp home" occurred soon after this. Is this coincidence, or could sucking in such gunk trigger such a fault being registered?

Advise is to stick the car into the dealer for a check - I don't pick up the cost so I'll be doing it anyway, but would be handy to know.

 

[paulfoel]

Had a pants journey into the office this morning when the car switched into "limp home" mode (lack of power, limited revs, etc). Turned it off, restarted, draopped back into limp home after 100m.

Mobilio came out to the office - Error 0202 registered (low boost). The guy cleared the code and a test drive didn't reproduce the problem.

The question is that I had to follow a nasty truck chucking out oily gunk from it's rear end - the front of the car looks pretty grotty and it's a nasty, oily residue. The drop into "limp home" occurred soon after this. Is this coincidence, or could sucking in such gunk trigger such a fault being registered?

Advise is to stick the car into the dealer for a check - I don't pick up the cost so I'll be doing it anyway, but would be handy to know.

I get a similar thing with mine intermittently.

Someone suggested checking the MAF for gunk. (http://www.mbclub.co.uk/forums/showthread.php?t=26300)

Maybe the crap off the lorry has gunked up the MAF.

 

[spitzkop]

On the 220cdi engines, the gunk wont get as far as the MAF unless you have a damaged air filter. Look at the side of the air filter, is the meter all white, all red or moving over to red? Red = time to replace air filter.

Could just be your engine was starved of sufficient air due to the crap it was sucking in.

Other than the above, the MAF may requiring a cleaning/replacement, in which case expect some performance/economy problems and a repeat of what you encountered.

 

[Dieselman]

Most likely cause is the turbo wastegate stuck open so caused low boost then limp home ensues.
The wastegate shaft needs greasing with the special high temperature grease.

 

[spitzkop]

Most likely cause is the turbo wastegate stuck open so caused low boost then limp home ensues.
The wastegate shaft needs greasing with the special high temperature grease.

Hi Dieselman,

On the 220/270/320 cdi engines, the Turbo is a Variable Nozzle Turbine design, not a wastegate. These devices have a smaller compressor wheel and need to be running at all times otherwise they choke or stall the engine. They are setup so that when there is no activation by the BPCVT (Boost Pressure Control Valve Transducer), they spin so that the air coming out of the compressor is equivalent to normal atmospheric. The activator arm engages the exhaust nozzle over the turbine to increase speed, therefore increasing boost. The plus side of them is that you get very little turbo lag.

If the BPCVT goes faulty, or the Boost Pressure Sensor (at exit from Intercooler) doesnt register sufficient pressure for a given activator arm position and boost charge temperature, then the ECU shuts the control mechanism off and enters limp home mode.

 

[Mr E]

Thanks guys - interesting comments.

An update - car was fine leaving the office, 50-60 on the dual carriage way and feeling OK. Through the outskirts (roundabouts and such) still feeling OK. Then a good 5 - 7 miles at 70-80. All OK until the roundabout at the end. Stopped for the traffic - and then back into limp home as soon as I went to pull away.

Pulled over a few miles up the road, turned off, pop into shops, back in the car, all OK again for the 10 miles of fast dual carriage way and country lanes back to Chez E.

Booked into favoured dealers next Wednesday...the other one nearby never seems to get things right first time so much rather wait an extra couple of days...

 

[Mr E]

Car shut down completely - so Mobilo came out again. Error P0299 Turbo/supercharger underboost.

Guy spent about 90 mins stripping things down to get a good look at the turbo and pipework - nothing going so recovered to MB Brighton...

 

[Brian WH]

Car shut down completely - so Mobilo came out again. Error P0299 Turbo/supercharger underboost.

Guy spent about 90 mins stripping things down to get a good look at the turbo and pipework - nothing going so recovered to MB Brighton...

They changed my Turbo when I had a similar problem.

 

[spitzkop]

They changed my Turbo when I had a similar problem.

It could be a simple item such as a leak in the Intercooler, the boost pressure sensor being faulty (or caked), the Vacuum system being under pressure, the Boost Pressure Control Valve Transducer being faulty, the vacuum pipework having a leak.

I spent many a weekend stripping, testing (I have CarSoft) analysing and so many simple things can log an error, and so many major items (such as a blocked exhaust) will not!!

Needless to say, if your under warranty, the dealership wont care what they replace, its all work for them. When Turbos go, they really go (noise, engine destruction)! I experienced total turbo failure in an RS I owned, destroyed the engine completely!!!!

 

[Dieselman]

Probably the variable vane actuator ring is sticking so the turbo loses boost.

The first hit will be to grease it after that a replacement.

 

[glojo]

Hi Mr E,
May I suggest a quick read of this link?

Regards,
John

 

[Mr E]

Cheers John...I'll ask them about that.

Wasn't too impressed when the dealer phoned on Monday to ask where to pick the car up from...although the young lady did explain that she was working through the booking list and didn't know mine had been recovered in over the weekend.

Ah - just had a call from the driver who's outside my old house waiting to collect my car!!!!

A quick call to the dealer I think....

 

[pammy]

ooops!

Hope they manage to get this sorted be interesting to know what the actual fault is.

 

[Mr E]

Not the wastegate, turbo actuator ring, intercooler....

New cats, being replaced under warranty.

Technician said that they had broken up, reducing flow, and thereby generating the error. Reckoned it must have been a fairly sudden failure as it went from "underboost" to "complete shutdown" in order to protect itself.

So she should be back tomorrow night - anything else that anyone should think I need to keep an eye on over the next few days/weeks.

Also - mentioned the recall y'day that Glojo posted. He confirmed that all the latest updates and fixes will be applied before it returns.

 

[spitzkop]

Definitely a cause, as a blockage will prevent normal gasflow and the turbo spinning up sufficiently. I couldnt simulate this with the car parked up in drive, but no doubt driving would do the trick.

But on a 2004 220cdi? What mileage? Also, you should have heard the cats rattling away. These machines have a pre-cat just after the turbo, then a multi-way cat just about under the centre console, well within hearing range (unless Stereo turned up full ). Nice to find out if this is the true cause though, because a guy from Gibraltar on the other forum had his cats replaced, similar fault to yours (except from total shutdown) and it did not rectify the fault!!!!

 

[Mr E]

Hi - no rattling (and the Mobilo guy didn't pick it up either). Car has done 80k.

Limp home to shutdown was 40-50 miles total mileage - tech's thought was that something internally broke rather than a gradual degradation.

We will find out tomorrow what happens......

 

[Mr E]

Hmmmmm.....

New cats are in - dealer took car out for a test drive. Straight into "limp-home" mode...

Connect up to diagnostics - now overboosting! Call to MB tech line results in a couple more tests and a new turbo on order, delivery tomorrow.

Ho Hum...

 

[spitzkop]

Hmmmmm.....

New cats are in - dealer took car out for a test drive. Straight into "limp-home" mode...

Connect up to diagnostics - now overboosting! Call to MB tech line results in a couple more tests and a new turbo on order, delivery tomorrow.

Ho Hum...

Plug and Pray ... why? The actuator arm is adjustable on these Turbo's, so if overboost is occurring, then you can tweak down the amount of activation. Installing a new turbo will just have a factory calibrated arm position, so it may work, interesting to see if it does.

 

[Mr E]

Got the car back last night - great after a week in a Focus (don't even ask).

All works and sounds good - even seems quicker (but that might be down to the previous week's car...). Car has been valeted as well (yes, not just cleaned) so I'm quite happy again.

Spoke with the techie and he said that DC asked for the parts to be sent back to Germany for further investigation. Presumably to confirm whether one failure caused the other or it was all an unhappy coincidence. Don't expect I'll hear the outcome...

All in all, a reasonable experience. Dealer kept me informed what was happening and I could speak to the technician directly as well who has only to happen to explain what had gone wrong and what was happening.

 

[spitzkop]

Good to see all's well, just a shame they didnt elaborate on the cause. Probably find the Turbo will be checked over, re-calibrated and re-stocked as a Mercedes Approved re-conditioned part! I was flabbergasted when the cost of the re-cond unit from Merc was almost the same as a new part. Turbo technics advised that only Garret were capable of re-conditioning them, so re-cond units were almost as much as new.
For anyone else needing a new Turbo, check-out www.ebay.de and look for Mercedes Turboläder (part number helps as well), they appear occasionally brand new at less than half Mercedes price.