prydz

Hi,

I'm completely new to this forum, but thought I could see if others have had similar problems/experiences with their Mercedes. I drive a 2009 GLK220 CDI.

In essence, over the last 2 years my GLK has 6 times displayed a check engine sign when accelerating on a highway, usually when going up hill. The car then enters into some kind of limp mode which allows me to continue my journey, but dramatically limits the cars acceleration power, to the extent that I need to hide behind slow going trucks in order to accelerate to my required speed.

I've already been to authorised Mercedes garages 5 times (in Austria, Belgium and Poland) and am scheduled for another visit (in Belgium) this Tuesday. Each time, seemingly different problems are found, the car fixed, but after a few weeks or months, usually when I again embark on a longer voyage, the problem comes back, leading me to believe that the issue has not been resolved at all.

Until now, the following things have been done or replaced:
- throttle valve replaced
- the Air Mass Sensor has been replaced
- electrical wiring harness has been replaced
- the diesel particle filter has been cleaned
- intercooler hose has been replaced.

I have now connected an OBD reader to the car. I first got a single P2279 code (Intake air system leak) and a pending P2463 code (Diesel Particulate Filter Restriction - soot accumulation). After a few hours, both codes appears as confirmed errors. In relation to this I wanted to ask if anyone has any views/ideas on the following:
- What can actually be wrong in view of the intake air system leak code?
- Given that I had to drive around a 1000km with the check engine light on and with very limited acceleration, could the soot accumulation be a result of this fault? Will it just burn away when the intake leak is fixed?

Thanks in advance.

Ausmbtech

The codes for the particulate filter are being generated because of the boost leak fault. If it doesn't have full control over boost it cant go into regeneration mode.

Can you hear a boost leak (loud sound of rushing air on the intake side of the engine) under heavy load before it goes into limp mode?

The common leak on the 651 engines (I think that's what you'd have) is the intake manifold bolts snapping allowing the intake manifold to come away from the cylinder head.

It's a long job to do, ALOT of stuff has to come off to get to it. It was quite difficult to diagnose the first time I came across this type of leak. Even with the tools to supply compressed air into the intake with the engine off to help find it I could only hear it and not see/feel the leak. It was still best guess rather than an absolute diagnosis.

Once you've fixed the boost issue you may need to manually regenerate the particulate filter for it to go back to normal operation.

prydz

Thanks Ausmbtech. I can't say that I heard a loud rushing of air when it happened; to me it was more like a sensation of a balloon going flat. I felt the car accelerating and then all of a sudden all of its energy escaped it.

I went to a Mercedes authorised service this past Tuesday (6th time) and they said that:
- Their examination did not reveal any leak.
- That the error codes were triggered by a blocked DPF, so they manually launched the regeneration of the filter.
- Regarding the intake leak code, they said that this code was triggered by the blocked DPF; that as a result of the blockage fumes were going back into the engine which triggered the intake leak error.

This did not sound very credible to me. I told them I disagree with their analysis and that in fact, the intake leak code appeared first; only a few days later did the DPF code appear (presumably after driving 1000km in limp mode).

For now the car is driving normally without any error codes, but I'm convinced that the moment I get onto the highway for a longer trip, I'll run into the same problem. I will be writing a complaint about this to Mercedes.

Ausmbtech

If you can't hear the sound of a large air leak and it happens so infrequently then it's unlikely to be a leak. Does the fault only occur when going up a hill or overtaking after an period of constant speed driving (10-15mins)?

Do you know if you have a 646 or a 651 engine? Single turbo or twin turbo?

prydz

The problem's regularity/irregularity is what is driving me crazy. It has occurred 6 times so far when driving on a highway, usually when accelerating uphill - when I would be trying to accelerate from around 80km/h to 120-140km/h. The problem isn't easily repeated however. Sometime I can drive 500km without any issue and sometime the check engine sign comes on.

I know that the check engine control can actually mean several faults. My suspicion comes from the fact that a similar case appears 6 times over the span of 3 years, always in similar circumstances.

The engine is a twin turbo 651.

Magda Mercedes

Hiya.

First of all, I realise that this post is not new, but I have the same problems (in addition to a few others).

I drive a 2011 E220 CDI (OM651-924 engine) and it is driving me absolutely mad.

Honestly, the story is way too long and tedious, but in short it started one hour after I bought it.
Engine-light, limp-mode and OBD told me soot-accumulation in DPF.

I took it out, cleaned it, and had a Merc-mechanic force regenerate the DPF.
All good until P2279 (intake air system leak).

After thousands of $ and several trips to the Merc-garage, they still didn't find anything wrong. Pressure-test was all fine, diag was fine, and regen was performed.
Worked ok for a week, the new P2279.
Same all over again, still found nothing, regen, worked fine for a week...and repeat.

By chance I discovered the problem; loose intercooler-hose from IC to intake.
Bought new (as safety-clamp was broken and not sold seperately), mounted and all good for two days, then P00AF, P2251, P0236 and P2263. And car tried regen EVERY SINGLE TIME I started cold engine.

Took out the O2-sensor (lambda) and cleaned it using compressed air, same with temp-sensor in DPF.
Worked like a charm...for 4 days, then P2263 again. But now regen happens every 3-5 days.

Then one day I got P0087, P0263, P0266, P0269, P0272, P0563 and P0500 all within 3 seconds, and the engine stopped. Turned off the ign, tried to calm myself, tried to restart and started as if nothing had happened.
Found a few cables with "gnaw-marks", fixed them and still P2263.

Have checked IC-hose and now loosing my mind. Still P2459, P2263 and P2279...every time I drive, every day, several times a day.

Can anyone help, please?

arturka

Hello I have the same problem
going to highway about 10-20 minutes. 110-120km/h , then i have brake down to 80km/h , and cross speed radar. and then accelerate from 80 to 120km/h to small hill, and abot 90-100km/h - Chek engine ,
my diagnostic programm show ne P2279 inteik air system leak.

How can i Fix this problem?

Magda Mercedes

Hi Aturka.

In my car, a E-220 CDI (S212-Om651/924) I tried many things.
First, make sure it is not your DPF that has become clogged.
Next, check airhose leading from inter cooler to intake. A common problem is breaking locking clamp.
If no errors are found, use an OBD-tester to monitor Cat-temp (DPF), MAF, MAP and TPS.

In mine, TPS indicate normal when re-generating, but wrong when normal procedure.

I will take mine to the garage in two weeks to see if they are able to re-calibrate TPS (absolute throttle position sensor).

Mine indicates constant 50+% when driving, when idling downhill, it indicates 87%.
As a result, fuel/air mix is wrong, hence soot and P2279.

I also get P2263 (turbo/supercharger), but this bus due to error in TPS, giving wrong value to correlating MAF/MAP-value.

Let me know how it goes. 😉

arturka

may be it is vacuum pump?
because my brake peral is very hard from mormimg
and i hear I hear interesting sounds when you press the brake pedal and hold . when I release the sound disappears .
Whether it can be connected with an error p2279?

Magda Mercedes

Yes, maybe...as if you have a vacuum leak, the bypass-valve for the turbo will be open at all times.

arturka

i have delete dpf filter (cut it) and remove EGR now its ok and taake chip tuning now i have 200hp 500Nm
the problem was dpf filter

Magda Mercedes

Excellent news!!!

In my car, the problem was actually charging air-pressure sensor.
I changed that one, and car is as intended. :-P

arturka

magda i still have problem on highway p2263 p2279
where is air pressue sensor and number?

arturka

what sensor you change?
This?

Magda Mercedes

The charge-air pressure-sensor, located at the base of the EGR-valve housing.
On the S212 engine, you first need to remove vacuum-housing on the side of the EGR-cooler. After that removal and insertion is easy.
Manual specifies 3-4 hours... I can do it in 15 minutes.

Magda Mercedes

For P2279 make sure to check airhose leading from turbo to intercooler, and from intercooler to intake.
The locking-clamps are a subject to failure.

Also...do you loose cooling-fluid? Check EGR valve and cooler to see if you have moisture underneath.
If so, that is the EGR leaking, resulting in malfunction and short-circut the charging-air pressure-sensor.