Dpf issue

[Jonwilko]

I have a e250 cdi blue efficiency estate, built in 2011. Recently the engine management light came on and car went into limp mode, won't rev above about 1500rpm.

Went to local garage and they said exhaust pressure sensor was problem but after fitting new one the problem remains.
After an unsuccessful attempt to sort the problem by using an additive and trying to take car for a longer drive at adequate revs to burn off soot, the light stays on. The problem was that in limp mode it was difficult to get the car revving fast enough. It is an auto so I tried all 3 modes. Perhaps I did not follow the clearing protocol correctly.
So I have booked it into an indie specialist in Somerset next month.
Is it wise not to drive it until then?
Could it be another issue, I am not certain that the garage who did the initial work have the correct OBD equipment. I think STAR is the best one.

Any advice about attempting self clean of dpf, or other issues which could be causing this, I am grateful.
Thanks

 

[Larkone]

You are chasing your tail until you know what the codes that caused the EML are. STAR is your best bet because it can go deeper than other code readers.

 

[M80]

Usually the limp mode prevents revs over 3k, so 1.5k presents quetions as to why.

I don't read that a forced regen was attempted.
If regen were inhibited the soot level may be higher than the ECU will permit a regen at. But there could be many causes.

If you continue to run the car you will continue to clog up the DPF.

AS above, you need the codes, by an Indie that has the right kit and knowledge.

 

[LostKiwi]

It's quite possible the DPF is a clogged it's inhibiting the ability of the car to rev. Until the DPF issue is resolved don't drive it as you'll make it worse.

And 8f anyone suggests doing a dpf delete walk away very quickly as that's not a fix of the underlying issues.

 

[Jonwilko]

Thanks guys I appreciate your help

 

[Manc Rick]

Yes, and I would add that IF it is the DPF that is blocked, there will be an underlying reason why it is becoming blocked, ie, getting it unblocked by forced regen and/or cleaning won’t fix the issue.

I’m sure an indie specialist will get you sorted. I wouldn’t drive it in the meantime.

 

[tpn]

What codes did the garage get to indicate the "exhaust pressure sensor"? without codes with this issue you are wasting your time....and doing further damage.

It is normally the differential pressure sensor that is at fault and when it is changed the tubes need to be checked to ensure that they are not clogged.
WHEN REPLACED (edit to avoid confusion).The car needs to be kept at a higher rev for 15 minutes to get the differential pressure sensor to adapt.

To save a lot o0f typing have a look at this Thread:- https://forums.mercedesclub.org.uk/...0-cdi-w204-curing-dpf-limp-mode.140226/page-3

 

[Jonwilko]

Thanks. The garage were a bit cagey and it's the first and last time I will use them.

 

[tpn]

Thanks. The garage were a bit cagey and it's the first and last time I will use them.

I would still ask them for the codes, you paid for them. Have a good read of the indicated thread.

 

[Jonwilko]

Thanks for the thread, it's really helpful. I will ask for the codes. I am using John Wareham at Class Mercedes in Somerset. He is really good, but I couldn't book it in with him as he is always busy.

 

[tpn]

If the DPF is blocking up it would not be good to drive it in the meantime.

 

[alcmackew]

I periodically get the EML on and the 3000 rpm limp mode. Have managed to clear this warning light a few times with high RPM and long driving. Given my commute is ~100 klm / day on freeways there's a lot of opportunity to give it the beans.

Service is due soon but I'm concerned how often the EML comes and then clears with a forced regen. Not keen to get a new DPF as I've heard the prices!

Currently sitting at 108,000 klms so perhaps too early?

 

[tpn]

Any reply would be pure conjecture without codes and knowing the conditions under which the eml comes on.

Driving hard -it is not necessary-is a passive regen, but I know what you are conveying and that terminology is correct in certain circumstances, for instance if you have a failing exhaust temp sensor, it could possibly increase the temperature sensed by the sensor and be sufficient for a passive regen to be triggered. A regular passive regen, should happen on a regular basis without you even knowing, when everything is working as it should.

It is possible that the EML is coming from a completely different issue. It could be a differential Pressure Sensor for instance, they work on sensing pressure and in the early stages of failure the extra hard driving could force it to operate; but that is just a wild guess.

I could guess that it is not the DPF as it is getting motorway driving; not a wild guess, but a guess nevertheless.

Get the codes before something unsavoury happens and come back here.

 

[alcmackew]

Thanks for the reply - yes next service at Benz should reveal the codes thrown up since the last service - it's had engine out work to repair oil leaks that thankfully haven't resurfaced. Had one of those bluetooth dongles fitted by Benz and the telemetrics since all look okay. If it's one of the sensors you mention I'll be sure to have it replaced.

Will report the findings once the workshop has had it. 38dgC over here today !

 

[tpn]

sooo while waiting for the codes, under what circumstances does the EML come on?
Did this start before or after the engine out?
Driving with an EML on will prevent the car from doing a passive regen.
Also doing too many regens will contaminate the oil and may lead to premature timing chain wear-not that it needs encouragement to wear.

Mazda 626's had a big problem at one stage, where excess regens were causing the fuel to get into the sump, leading to crankshaft wear.

 

[alcmackew]

Yes it's a bit random TBH. Starts off with the transmission doing a clunky downshift when decelerating and RPMs limit to 3000 max. Then the EML light comes on. Last time it did then the workshop did a remap of the transmissions shifting points and a forged regen.

Unfortunately I'm not sure if this was an issue prior to the engine out work as I just bought the car (see my other thread) and oil started leaking from the sump, switch over valve and oil cooler. Thankfully I was reimbued by the dealer after I had the work done at Benz but had to lodge a claim with the Motor Car Traders Guarantee Fund - 6 months later they coughed up under instruction.

Its fine again now - EMLs gone and transmissions shifting perfectly....as I sad next service in due in 2 weeks so will see what's up. Still happy with the car and its nuances just clicked over 10 yrs old.

 

[chopper_harris]

Folks

A note to warn any potential buyer of an icarsoft unit, I purchased an icarsoft MB3 unit to force a regen after replacing the forward DPF temp sender.

The regen process fails during a DPF fill level recalculate stage, and exits.

The only codes present are for DPF overfill, and two codes related to wing mirror heating circuits?

Support from icarsoft has been non existent, Barnett Davies has made several empty promises to provide a response, and is now ignoring my emails.

If anyone in the Warrington to Preston area has access to a Mercedes Star unit, and can help me to force a regen, I would be pleased to hear from you.


If you do buy an icarsoft unit, don't expect any level of support, they are truly pathetic.

Reply

 

[ajlsl600]

Admittedly I hav had no need to contact dealer, maker of icarsoft
But in my case to date I have found it a fine bit of kit
It saved my bacon last yr
I would quite like to understand the regen process and will look into that.

 

[tpn]

I have not had a problem with DPF regen request on an icarsoft, admittedly the MB 2. I would assume that the MB 3 would be better again.....but

B

 

[V6Matty]

I have not had a problem with DPF regen request on an icarsoft, admittedly the MB 2. I would assume that the MB 3 would be better again.....but

B

More likely is that there is still something else wrong that hasn’t thrown a code but makes the car abort the regen,
Code readers are really only as good as their operators, knowing how things should work for looking at live data goes a long way in getting issues resolved rather than just error codes.

Folks

A note to warn any potential buyer of an icarsoft unit, I purchased an icarsoft MB3 unit to force a regen after replacing the forward DPF temp sender.

The regen process fails during a DPF fill level recalculate stage, and exits.

The only codes present are for DPF overfill, and two codes related to wing mirror heating circuits?

Support from icarsoft has been non existent, Barnett Davies has made several empty promises to provide a response, and is now ignoring my emails.

If anyone in the Warrington to Preston area has access to a Mercedes Star unit, and can help me to force a regen, I would be pleased to hear from you.


If you do buy an icarsoft unit, don't expect any level of support, they are truly pathetic.

Reply

Sounds like your DPF is already full of ash