Sensor problems /DPF removal - would really appreciate advice!

[nidgemo]

EXHAUST SYSTEM FOR FOUR-CYLINDER DIESEL VEHICLES MERCEDES E-KLASSE [Car] [CHASSIS] (EUROPA)

The "cat" item 10 is two things in a single canister -first a catalytic convertor section and second a dpf section each section has a temperature sensor 235,240. The sensor that usually gives problems is the differential pressure sensor 370 which measures Exhaust gas pressure for and aft of the DPF section- and that's usually the sensor which indicates a blocked cat.

Thanks for that - this is what my scanner shows up - do you know which it is from that?

 

[grober]

Unfortunately it would appear to refer the temperature sensor before the catalytic convertor section rather than the one before the DPF section. Being flagged as out of range may mean its defective or it has a bad electrical connection. Unfortunately the engine ECU may rely on that sensor to be within a certain temperature range to initiate a regen cycle possibly meaning the car will never regenerate its DPF by Extra fuelling/EGR switching etc while that sensor is faulty.
Did the garage replace that sensor and cancel the code?
P042628
Full Diagnostic Trouble Codes List
Here's some background on the your OM 651 engine
http://autocats.ws/manual/sdmedia/mediadb/mb_Acrobat/einf/204/einf_br204_cdi_OM651__en.pdf

 

[nidgemo]

Yeah, that was my thinking - that the ECU would stop regen if that wasn't working...

In fact, since that error has shown up, the DPF level is showing as 0% - would that be the cause of that? Showing 0% due to inability of being able to measure it?

 

[grober]

I would assume that the percentage figure is derived from the differential pressure sensor reading??? Again if the sensor was faulty that should throw up an error messge? Did the specialist force a regen when the car was in the garage or has the engine warning light come on again. Remember there are two things which block a CAT/DPF --- ash and soot. While the larger soot particles can be removed by regeneration the smaller ash particles remain and gradually accumulate over time. The mechanisms of cats and DPF'S are different - with cats its a surface effect- gas passing over a chemically heated surface are changed so the chances of trapping are much reduced, with DPF's its a wall or sieve effect where gases pass thro passage walls into adjacent passages and get trapped in the process.
Understanding the Differences Between Ash and Soot | CTS

 

[Petrol Pete]

How are garages going to see any DPFs thru undertray panels that are fitted ? Majority of independent MOT garages have no electronics gear to plug in. I think this is all a big smokescreen (get it boom boom, smokescreen) and that this can’t ever be properly enforced. DPFs are one of the biggest con in cars that the government has ever done. I’ve never met a taxi driver with a new car that HAS NOT ADMITTED he’s had DPF troubles with it. I think most people who talk about this are ill informed and missing the point. The change is going to increase the sensitivity of the emissions test . One of the reasons being is that cars with DPFs are actually that clean when the gun is stuck in the exhaust to be checked. The emissions test reads nothing. So what they are doing are making the emissions parameters tests more sensitive. Wither u got a DPF or not if your oil filter is dirty and ur car ain’t been serviced properly then it will be a guaranteed fail and every garages nightmare with cars queuing up taking up more space. They are either going to fail your MOT on ‘ unable to check components under car’ ( due to undertrays) THIS IS NORMALLY AN ADVISORY. or going to charge you for the 5 minutes to take the undertrays off ????? No chance !

It's EU driven (read Germany) and that's the plan. Get all 'old' cars off the road so we can sell more. End of story.

 

[HITECH]

Just for the record. Majority of any errors (relating to engine management) in the ECU will prevent the DPF from re-generating. This is fact.
This is the question that has to be answered as grober asked:
" Did the garage replace that sensor and cancel the code? " .

The sensor being: * The Pre cat, upstream O2 sensor. Has it been replaced ? *

Here is some info I've copied/pasted from elsewhere:

* Locate the O2 sensor before the catalytic converter. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burn spots. Next is to check the connector for security, corrosion and damaged pins. With the engine running, the visual inspection should include identifying possible exhaust leaks. If its been a few years since the O2 sensor has been changed or it is unknown then replace it. *

Personally from my own experience Id put money on that the O2 sensor has packed in.

Read more at: P2628 O2 Sensor Pumping Current Trim Circuit High Bank 1 Sensor 1
Copyright OBD-Codes.com

Unfortunately it would appear to refer the temperature sensor before the catalytic convertor section rather than the one before the DPF section. Being flagged as out of range may mean its defective or it has a bad electrical connection. Unfortunately the engine ECU may rely on that sensor to be within a certain temperature range to initiate a regen cycle possibly meaning the car will never regenerate its DPF by Extra fuelling/EGR switching etc while that sensor is faulty.
Did the garage replace that sensor and cancel the code?
P042628
Full Diagnostic Trouble Codes List
Here's some background on the your OM 651 engine
http://autocats.ws/manual/sdmedia/mediadb/mb_Acrobat/einf/204/einf_br204_cdi_OM651__en.pdf

 

[tangey]

I'm on my fourth diesel, Mercedes-Benz, Jaguar and Audi, and being retired during my ownership of all of them and therefore an habitual short journey driver - 6000 miles a year - I've never had a single dfp or sensor issue. In fact I've never had a single issue of any type. Maybe it's the way I drive and maintain them and use only the best fuel and lubricants, I don't know, but to me dpf issues are urban myths, only giving problems to those who don't give their car proper care and maintenance. In my opinion, though I have only elementary 'mechanical' knowledge, the "independent specialist's" advice seems to be utter tosh and I'd ignore it.

urban myths...lol.

It's a very well documented issue, although the car manufacturers seem to have advanced their tech recently so it has become less of a problem.

I had a Volvo S60 for 4 years, which would go into limp mode a lot, however if I went for a decent drive as soon as the warning light came on, it would sort itself out. Leave it even a short while, and it had to go back to the dealer to force a regen. Around the same time I had this, I heard endless stories of dealers telling people that a deisel might not be for them if they did a lot of short runs. I also heard that Mazda was prone to this.
My next car was an XC60, I had it for 6 years, and it never gave a single DFP issue.
My current car is a GLC, and I haven't had an issue with it either, in 2.5 years, although it has just been returned back to me in the last hr, as the Nox sensor went faulty and needed replacing, so maybe I'm tempting fate.

All diesel cars with the same "car care" (i.e. none), same mileage (5-6K a year) and same driving style.

 

[David404]

On my previous car (Saab 95 1.9TiD) I learned to watch for when it was doing a re-gen - it was quite predictable at the same point on the way home from work - if the regen started I extended journey home, dropped a gear, got revs up to 2750/3000 to allow re-gen to complete. Have to say though I had issues (£2k) when I first got the car.

My experience - if you have a DPF equipped car it will take some management of re-gen cycles, you will need to be ware of what's happening.

Fortunately I'm not planning on swapping for 3 years or so but next car will be difficult choice.

 

[Petrol Pete]

I hear you guys when you talk about the Re Gen cycle and taking appropriate driving action to start and finish the re gen, either by going for a long drive or making the engine work harder by running in a lower gear etc.

But for every one person who knows what a Dpf is there are literally thousands who do not , 'car' people like us join forums and discover things about their cars but I know grown men who have absolutely no idea how a car works and have never lifted the bonnet. It is them that are going to get hit by the Dpf thing. I foresee a LOT of cars being scrapped over the next year or so because of this one issue.

 

[219]

How are garages going to see any DPFs thru undertray panels that are fitted ? Majority of independent MOT garages have no electronics gear to plug in. I think this is all a big smokescreen (get it boom boom, smokescreen) and that this can’t ever be properly enforced. DPFs are one of the biggest con in cars that the government has ever done. I’ve never met a taxi driver with a new car that HAS NOT ADMITTED he’s had DPF troubles with it. I think most people who talk about this are ill informed and missing the point. The change is going to increase the sensitivity of the emissions test . One of the reasons being is that cars with DPFs are actually that clean when the gun is stuck in the exhaust to be checked. The emissions test reads nothing. So what they are doing are making the emissions parameters tests more sensitive. Wither u got a DPF or not if your oil filter is dirty and ur car ain’t been serviced properly then it will be a guaranteed fail and every garages nightmare with cars queuing up taking up more space. They are either going to fail your MOT on ‘ unable to check components under car’ ( due to undertrays) THIS IS NORMALLY AN ADVISORY. or going to charge you for the 5 minutes to take the undertrays off ????? No chance !

Unless something has changed , testers aren’t permitted to remove undertrays, engine covers and the like ; they aren’t even allowed to lift fitted carpets to inspect the floor .
“I could not inspect the item because the rules forbid the removal of covers” is not a valid reason for refusal to issue a pass certificate.

 

[HITECH]

Yes I know the way the rules were. But things have changed. Advisories were given about undertrays stating unable to properly see lower components due to undertray. So if you cant see DPF from top due to the engine and components and you cant see the DPF from the bottom due to an under tray. How exactly is this going to be monitored ? Im thinking the only way is that cars equipped with DPFs are going to under-go an extremely sensitive emmisions test and if the DPF has been removed or tampered with then they are expecting higher emissions and this is where the tell tale sign of a removed or tampered with DPF is going to be found out. Thats my 2 bobs worth on it.

Unless something has changed , testers aren’t permitted to remove undertrays, engine covers and the like ; they aren’t even allowed to lift fitted carpets to inspect the floor .
“I could not inspect the item because the rules forbid the removal of covers” is not a valid reason for refusal to issue a pass certificate.