S204 C250CDi: DPF Restricted - Do I need a STAR diagnostics?

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DucatiEVO

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Joined
May 24, 2022
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115
Location
Oxford
Car
2012 Mercedes C250 AMG Sport Plus Estate
Read many a post on here about DPF issues and limp mode/limited 3000rpm's.

Got the dreaded DPF error on my cheap OBD2 mobile phone diagnostics, currently saying 'DPF Restricted', and whilst I can clear the error 'light' there is no change in performance or removal of the 3000RPM limit.

So far I have removed and cleaned the DPF, and fitted a new Merc pressure sensor, but it's made no difference.

Do I need someone with an actual Star diagnostic to 'reset' the DPF information, or can I get an iCarsoft that could do the same?

Thanks
Chris :)
 
Did you clear the pipes to the pressure sensor with compressed air? They can block up and a new sensor or dpf clean will not cure the issue. Just a thought
 
Did you clear the pipes to the pressure sensor with compressed air? They can block up and a new sensor or dpf clean will not cure the issue. Just a thought
TBF I have not tried that, but can try that this weekend. Was wondering if there was a diagnostic machine I could get to test anything like that etc.
 
An iCarsoft MB.II will reset a DPF.
 
My iCarSoft Pro will let you reset/replacement dpf so I think it depends which model you have.

What is the differential pressure saying at idle with the cleaned DPF?
 
My iCarSoft Pro will let you reset/replacement dpf so I think it depends which model you have.

What is the differential pressure saying at idle with the cleaned DPF?
I don't have a decent diagnostic unit as yet, only my mobile phone ODB version, which doesn't display any pressure stats sadly. :(
 
What fault code is it showing? Does it come back immediately or after a short drive?
 
True, but you need the information first, and for that you need the kit.
 
True, but you need the information first, and for that you need the kit.
Indeed.

In this case I would rather spend money on someone competent with Star/Xentry where a diagnosis would be assured 👍
 
The OP asked about diagnostic kit. In his place I'd get an iCarsoft; they're cheap enough, and an investment for the future.
 
A fair few videos on youtube showing mobile mechanics using long probes attached to Dpf cleaning products going directly into the system , cleaning it and then 'plugging in' and re setting.
 
What fault code is it showing? Does it come back immediately or after a short drive?
P2463 DPF Restricted - if I clear the EML light, the error it still there (don't have to drive it at all)
 
A fair few videos on youtube showing mobile mechanics using long probes attached to Dpf cleaning products going directly into the system , cleaning it and then 'plugging in' and re setting.
Yes, I've been watching a few and it does look like once you clean the DPF (I removed mine to clean it), you need to 'reset/replace' in the computer for it to update. I'm going to see if I can get a local 'Indy' with the Star system to do that for me and see what happens. :)
 
There is no need to get a DPF clean. You need to find the actual reason the DPF is reporting as restricted. Once the fault is cured the regen will take place.

Some live data with an Autel or similar is your solution. I have the Autel AP200 which is a dongle and connects to your iphone for the app. With this you can see the live data for the differential pressure sensor etc and also get a read out of the last regens and if they took place or failed along with a reason it failed.
 
There is no need to get a DPF clean. You need to find the actual reason the DPF is reporting as restricted. Once the fault is cured the regen will take place.

Some live data with an Autel or similar is your solution. I have the Autel AP200 which is a dongle and connects to your iphone for the app. With this you can see the live data for the differential pressure sensor etc and also get a read out of the last regens and if they took place or failed along with a reason it failed.
AFAIK if the car doesn't manage to do a regen in a certain time, you eventually get the DPF restricted error, and then it needs resetting etc. I've already cleaned my DPF having hit this error now because it had failed regens before (not driven enough). :) I've got a basic OBD reader and my phone, but it doesn't have that much detail apart from the error codes. Hence I'm going to see if my local indy can plug it in and do a reset for me.
 
What you need them to find is the reason it doesn’t complete a regen.
It can be a number of things. In my case a while ago it was a 12v battery issue. A new battery sorted it

A Mercedes Indy said the DPF had to come off and be cleaned etc etc etc and some other stuff blah blah circa £700.

The diagnostics thing I use quite clearly said “ reason for non completed regeneration - battery voltage too low. “

I’d been delaying changing the battery as the car was in constant use. After 3 days of no use the battery was flat and the car wouldn’t start.

Basically you need to find the root cause as resetting things is a short term thing

The Autel AP200 is their cheapest diagnostic machine and for me it’s been invaluable. Below is a screen shot of the report it generates showing the last 16 regen attempts. Some fail and the reason is shown. It’s an a very useful tool which has saved me hundreds of pounds. It also shows live data such as fill level, exhaust pressure, DPF temperature etc.

Worth remembering if there are and stored and current codes triggered that the car won’t regen. And an active code doesn’t always give a CEL on the dash.
 

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