C204 2011 Exhaust Back Pressure & Boost Pressure Sensor

[tgl3]

Hi guys,

I’ve recently bought my 2011 C-Class C220 CDI Coupe. Everything works fine until yesterday the Engine Management Light came on, so I sent the car to my local Halfords to check it and then two error codes were found (P047128 & P024028), which indicates that the Exhaust Back Pressure Sensor 1 and the Boost Pressure Sensor for the low-pressure turbocharge have malfunctions (As the photo shown). Strangely, according to the receipt provided by the previous owner, the pressure sensor seem replaced two months ago (receipt photo uploaded) which unlikely to have malfunction at such a short time. As Halfords don’t know the exact cause of this so I took the car to another local garage with good reputation to seek a second opinion, they told me that it might be something wrong with the DPF probably because it’s clogged, and they advised me to have a DPF clean.So today I brought my car back to Halfords to have a “DPF Flush” service they provided and speak to the mechanic about this, the Halfords mechanic however told me that the DPF clean is highly unlikely to work and rather suggested the car may need a new DPF. Now I’m really confused and don’t know what to do; if the replacement is really required I know the cost is hefty but anyone has any experience on that can tell me the approximate cost for that work?

The car now has 139,000 mls on clock and the only symptom leads me took the car to check is that the Eco mode (Auto Start/Stop) isn’t working. Few seconds after the ignition on the Eco light on the centre console and also the Eco symbol shown on the dashboard will disappear, neither yellow or green Eco symbol will be shown. No limp mode and I can’t really find any other symptom...

Thanks guys in advanced for any help given!!!

 

[jasons]

I would say the DPF is probably blocked and may need a forced regen to clean it out,i would try and seek out a Mercedes specialist in your area who may be able to advise you better,i am only guessing that the eco isn't working because it requires a regen so it turns it off so the engine cannot turn off on its own.

 

[Tonygw]

Sorry to hear of the troubles, dpf,s can be cleaned very well but Halfords is a parts fitting place really and won't be much help here.
It doesn't sound like the dpf is at fault though. You may need a decent merc specialist as they will know much more and be much more willing to diagnose the issue properly. It could be something as simple as a split hose causing the issue.. if it is the dpf you can remove it a pour in dpf cleaner and jet wash it out. Takes a good 30-40 mins to do properly until the water runs clean out of it but will fix any clogged dpf issues.

 

[tgl3]

I would say the DPF is probably blocked and may need a forced regen to clean it out,i would try and seek out a Mercedes specialist in your area who may be able to advise you better,i am only guessing that the eco isn't working because it requires a regen so it turns it off so the engine cannot turn off on its own.

Had the DPF cleaned at Halfords today but doesn’t really work as the EML still on. I don’t even know if they had really done any regeneration as it really makes no difference...

 

[tgl3]

Sorry to hear of the troubles, dpf,s can be cleaned very well but Halfords is a parts fitting place really and won't be much help here.
It doesn't sound like the dpf is at fault though. You may need a decent merc specialist as they will know much more and be much more willing to diagnose the issue properly. It could be something as simple as a split hose causing the issue.. if it is the dpf you can remove it a pour in dpf cleaner and jet wash it out. Takes a good 30-40 mins to do properly until the water runs clean out of it but will fix any clogged dpf issues.

Agreed.
Halfords doesn’t really helpful at this point...they did the “DPF Deep Clean” for me but doesn’t makes any difference. The EML still on and they couldn’t tell where the issue is. As I rarely visited any garage other than Halfords because I used to do services and MOT at Halfords and didn’t have much complex repair work so used to stick on Halfords, do you have any recommendation on MB Specialist in Coventry?
thanks for all help and advices given

 

[Tonygw]

I think there is one in Nuneaton, or if you can make it to Loughborough, MB automotive are really good. I use them and the know these cars inside out. And they have the proper diagnostic kit/software. The Halfords deep clean for the dpf doesn't really do much. The only way to clean properly is to take it off to clean. Hope you sort it

 

[Tonygw]

I have heard these guys are excellent

Family-run Mercedes-Benz specialists in Nuneaton, Warwickshire | Mercland

Whilst we specialise in Mercedes-Benz, we hold an extensive range of second hand cars featuring all makes and models in our showroom in Nuneaton, Warwickshire. Mercland can provide the right car at the right price. We also do servicing and MOT at our garage, Whittleford Auto Services.

www.mercland.com

 

[tgl3]

I think there is one in Nuneaton, or if you can make it to Loughborough, MB automotive are really good. I use them and the know these cars inside out. And they have the proper diagnostic kit/software. The Halfords deep clean for the dpf doesn't really do much. The only way to clean properly is to take it off to clean. Hope you sort it

I visited both MB automotive and the Mercland in Nuneaton today. They are both fully booked for this week and cant book me in until the next week. But the MB automatibe really impressed me as they looks really professional and the mate in reception gave me some potential reasons for that and proper advice. Will wait and see
Cheers buddy!

 

[Tonygw]

Nice one, let us know how you get on.

 

[OneForTheRoad]

Fairly sure the stop start has it's own battery .

 

[Tonygw]

Yeah it's in the boot.

 

[tgl3]

Morning guys,

Hope all of you enjoyed a lovely weekend

This morning the car has been checked by mechanics and something strange happened; when they plugged in the OBD scanner this morning, they could only find the error code for the Boost Pressure Sensor but not the code for the exhaust back pressure sensor. Could it probably be relevant to those DPF cleaning works done last week? Last week I sent the car to Halfords to have a DPF flush (“DEEP” clean as they said) and put a bottle of Redex DPF cleaner into fuel tank afterwards , following by an 100 mls journey on motorway to have it worked.

For the boost pressure code, they told me that there are two sensors needed to be replaced, one near the turbocharge and one near a manifold (not sure which one it is). I doubt if it is really the sensor issues or probably something more deeply has issues but not discovered.

It’ll be great if you guys can give some opinions thanks!!

 

[Tonygw]

A strange one this. I am wondering if you may have an air leak or pipe thats come dislodged somewhere throwing error codes. It might be worth just checking carefully all the pipes around the turbo and air intake.
Splits can be VERY hard to spot so you need to look very carefully. My local garage (MB automotive loughborough) used a smoke machine on the intake to find the split in the boost pipe on mine when it split the pipe. I dont think I would have found it myself.

You dont want to go randomly changing sensors as that could get expensive.