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Adamantia

2009 E61 530D unusual DPF problems

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Hi All

 

I'm not one that normally has issues diagnosing complex problems, but this one is beginning to really stump me. Apologies for the length below, but some of the details might be important.

 

2009 LCI E61 530D, manual gearbox owned since Jan 2018 and done 25k since then, now at 156k miles. Previous owner had the DPF gutted and mapped out a few months prior to selling due to issues. It also had a stage 1 remap done at the same time, and was sold with just shy of 12 months MOT.

 

Car drove great, but the cat had clearly been removed along with the particulate filter so it stank like a bus. Only smoked briefly at cold start, and on hard acceleration (especially after pootling along calmly for a while before hand).

 

After purchase I quickly found, with little surprise, that both thermostats were buggered and the car never got above 70C, plus had numerous glow plug faults. I replaced both thermostats, all glow plugs and controller. Car was then faultless and warms up and runs at 90C no problem.
I also discovered the swirl flaps were blanked, and whilst on the LCI M57 they shouldn't be an issue it didn't really bother me.

 

My commute is 35miles each way, of which 20-25 minutes is on fast dual carriageway. i.e. pretty good conditions for a diesel DPF

 

In December I wanted to reinstate the cat/DPF and map it to expect the DPF again. This was done both to make sure I didn't have any MOT issues with the new changes brought it (MOT end of Dec) and to fix the terrible bus smell. Since I've had previous success with aftermarket new DPFs, I bought and fitted one to replace the gutted BMW can. A local tuner took a stock ECU file for my ECU version, coded out the EGR but left the DPF behaviour, and gave a new stage 1 remap (old one was pretty poor, though it did drive ok).

 

After several problems making it gas-tight on the DPF/turbo flange, I found that I was getting excessive exhaust back-pressure and thus the car would constantly be trying to regen to clear the apparent soot load. I replaced the aftermarket DPF with a refurbished OEM one from Germany (i.e. a used DPF that's been cleaned out of soot and ash). Unfortunately whilst there were some improvements, I'm still getting the same behaviour.

As a cheap and simple form of troubleshooting, I've replaced both exhaust temperature sensors and the pressure sensor with used BMW items. No difference noted. There are no DME error codes, and the sensor readings seem sensible.

 

Even after an apparent regeneration, the back-pressure at idle when cold is ~12-16mbar. Once it warms up to ~200-250C the pressure increases to ~24mbar. The ISTA/DIS tests show the back-pressures are:
idle - 22mbar (limit 35)
2000RPM - 46 (limit 75)
3000RPM - 92mbar (limit 130)
cutoff/4kRPM - 157 mbar (limit 200)

 

I've noticed the car was call for a regeneration once the soot mass rises above ~42g. However even after a regeneration (which might drop the soot down to ~28g over 45 minutes or so), it very quickly rises back up to around 39-40g. It then increases slowly until it starts another regeneration cycle. It seems to estimate soot mass both from the pressure sensor but also an estimated curve based on how long it is regenerating and what temperature the DPF is at. Once it finishes a regen, the soot estimate quickly rises back up using the data from the pressure sensor alone.

 

When it does a regeneration, the temperatures behaviour a bit oddly. It will go 'active', exhaust temp rises quickly to 520-600C. The DPF exhaust temp lags behind a bit (since it has the cat between it and the first exhaust temp sensor). Once the DPF temp reaches 520+, the regen 'active' flag goes off. The exhaust temp quickly drops, and the DPF temp lags behind a bit. Once the DPF temp drops down below ~420C (after 20-30 seconds), the regen goes active again, and the cycle repeats. The system yo-yos like this the entire time, until I end the journey. If I 'force' a regen and drive at 70 continuously, it will do this behaviour for about 30-40 minutes, then actually 'complete' the regen and resets the miles-since-successful-regen counter to 0. I think this is just a time-out. I've also noticed that the measured back-pressure drops by ~1/3 when regeneration is active - I think this is the throttle plate (just before the EGR) partially closing to increase exhaust temps (I can also see the commanded EGR/throttle increases from 5% to ~30-50% at the same time). The EGR tube is disconnected and blocked.

 

From previous experience, others people's descriptions and a few graphs of other people troubleshooting the M57 DPF, I would expect when a regen starts the system will get the DPF temp all the way to 600C+ and it will stay up there until the end - i.e. not yo-yo between 400-520C.

 

I'm wondering if this is my problem (i.e. it doesn't really get and stay hot enough to fully burn off all the soot, but is enough to maintain a soot level around 40g).

 

Alternatively problems I could have, in order of likelihood:
- Both aftermarket and 'cleaned' OEM DPF actually have ~40mbar soot equivalent back pressure, and showing the same issue.
- New ECU map is wrong, either for measuring back pressure or DPF regeneration
- Faulty DME/wiring affecting the pressure sensor readings (i.e. back pressure is actually lower)
- DPF is clean/clear after regen, but rest of exhaust system has partial blockage
- Engine is producing so much soot, even during regen, that DPF is always partially blocked. I have seen some comments that blanked swirl flaps increases soot emissions, though only in town driving.

 

I can actually feel when the regen goes in and out of active, probably as I have a manual gearbox. Slight change in available torque for the same accelerator position. Apart from that, the only sign of a regen is if I come to a stop when temps are still high, the engine bay smells slightly 'hot' (creeps in through air vents). Exhaust tips have remained clean since I fitted the DPF (they were filthy before!).


Reported ash mass (which reset when installing the new DPFs and using ISTA to tell the ECU this) is increasing very slowly, around 0.1g per 100 miles. It also increases by a fixed amount of 0.22g each time I 'force' a regen. It's currently at a reported 0.51g. I'm not sure how the ECU calculates this value.

 

Attached are some graphcs I've made of logged data to show what is happening: 
Aftermarket DPF, attempting regeneration, long drive

OEM DPF attemped regeneration

OEM DPF, regeneration stopped by disconnecting throttle actuator

 

TL;DR
Is my DPF regenerating properly? If it is why do I have such high backpressure even after a successful reg?

 

Thoughts and advice much appreciated!

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Interesting post, this is a real minefield. I have a similar issue myself, I've replaced thermostats/glow plugs, cleared codes etc trying to get my DPF to 'behave' normally, but I'm still none the wiser. I managed to force a regen a couple of months ago but since then (2k miles) it hasn't done another. I also have blanked swirl flaps and have been told that could be the culprit, but I do hardly any town driving (my average speed is over 40mph.) So having spent 18 months since buying the car worrying about the DPF, I'm now just going to enjoy driving the car and worry about it when something actually goes wrong.

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3 hours ago, edd_jedi said:

having spent 18 months since buying the car worrying about the DPF, I'm now just going to enjoy driving the car and worry about it when something actually goes wrong.

^^. You seem to have gone to a great deal of trouble trying to largely return the car to its original spec and to eliminate problems, so all credit to you for that. When we bought our E60 nearly 4 years back I spent ages worrying about the DPF (that's when I wasn't worrying about catastrophic failure of the autobox).

Diagnostics via Carly gave me reams of DPF data but as I didn't know whether many of the readings were within acceptable limits I wasn't sure if the news was good or bad. Apart from thermostats being stuffed that is. Since replacing them I check the coolant temperature and how often it regens and just use it.

I'm not saying my approach is the right one, but I enjoy the car much more now I'm not worrying about it all the time.  :)

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I am very interested to hear  what other people have experienced with the DPF. So many people remove it as soon as there is any problem, when often it's just a symptom of an underlying problem. This is doubly annoying when the LCI DPFs are meant to have much longer service lives.

 

Part of my in depth look at this is having spent so much time and money (and bruises, the LCI DPFs are really awkward to get in and out) it isn't behaving properly.

 

One of the problems with the constant regens is my average MPG has dropped from 43 to 36, which when I'm doing 20-25k a year starts to become noticeable!

 

 

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2 hours ago, Adamantia said:

I am very interested to hear  what other people have experienced with the DPF. So many people remove it as soon as there is any problem, when often it's just a symptom of an underlying problem.

 

Nail on the head. People think they are solving the problem by removing it, but the DPF itself doesn't fail, they are still driving around running too cool, no working glow plugs etc.

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So, is the EGR still disabled?

Running at higher revs, it won't be doing much, but at idle the EGR will be recycling up to 50% of the exhaust gasses back into the intake. I know this sounds like a bad thing, but the idea here is to reduce the emissions that are coming out of the exhaust, which it achieves by sending unburnt fuel (inefficient combustion at idle, not helped by the lack of swirl flaps) back through the engine again.

 

On your car, all of this stuff goes straight through to the DPF, which is just doing it's job and collecting soot etc. The rate at which this stuff accumulates is far higher without EGR and swirl flaps, which might explain why your car feels the need to clear out the DPF so often. As you said, on an LCI the swirl flaps shouldn't present a problem, so I'd put those and the EGR back in the system and re-evaluate.

 

 

Steve

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While not agreeing or disagreeing with other comments, looking at your graphs, the regen status "yo-yos" from on to off every 20 seconds exactly. This can't be right. It's supposed to come on and stay on for 10-15 mins until complete. I would be looking at the software (mapping) side of things as the root of that particular symptom. 

 

Keliuss

Edited by keliuss

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You will need to put the car back to stock to really know, having had similar issues myself with frequent regens I have just fitted a brand new genuine inlet manifold to put the flaps back, the cars spend 90% of the time under 2k revs when the flaps are working to reduce emissions.

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Thanks for all the comments.

 

I'm having it put back to stock later in the week. The mapper confirmed the EGR has been disabled in software.

 

I've done about 150 miles with the throttle plate disconnected - this seems to stop the ECU from attempting to regenerate. Interestingly the soot mass increased to about 54g (from ~45) after about 10 minutes; It then stabilised and has slowly increased over the miles to 64g. I think this shows the 'real' affect of soot, so hopefully if the stock map fixes the regeneration behaviour, I can get a full regen in to find what the actual clean back-pressure is.

 

I think I will bite the bullet and put flaps back in the inlet manifold. I've seen the re-manufactured inlets from germany for 190euros. Is this worth it vs buying a good condition used item (and new gaskets) for £70?

 

28 minutes ago, GoNz0 said:

You will need to put the car back to stock to really know, having had similar issues myself with frequent regens I have just fitted a brand new genuine inlet manifold to put the flaps back, the cars spend 90% of the time under 2k revs when the flaps are working to reduce emissions.

 

That's interesting - have you found if this helps reduces how often it regens?

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I decided against a refurbished as they have cheap seals that leak, by the time you price up BMW seals the manifold doesn't seem that bad for a genuine new item

As for the regens it will be a while before I know, after it does one I will be monitoring it to see how long it takes.

I also will be picking up a used DPF with lower miles to clean out as a spare in the next week in case mine is past it.

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@GoNz0, a friend of a friend went into business recently specifically cleaning DPF's for the motor trade. I haven't seen it but his business is built around a small van sized piece of equipment imported from Italy at a price of approx. €50k. I think I read you cleaned yours with a power washer and chemicals (might have been someone else though). Anyway, my point is if you buy a backup maybe consider having it cleaned professionally as I can't imagine anything you could DIY would compare to whatever it is the Italian equipment does.

 

Keliuss

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Do you have his details?

 

Yeah chemicals and jet wash, an overnight soak and I did remove a lot of compressed ash. I have no one near me with proper equipment just the cowboys who inject a cheap can of cleaner and force a regen. 

I was considering attaching the DPF to a length of drain pipe and forcing water through with my drain rod kit as I got most ash out by physically filling the DPF with water and blowing it through with my lungs :lol:

 

Glad I had the gates shut, the neighbours would have been pissing themselves. 

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8 minutes ago, GoNz0 said:

Do you have his details?

 

 

Well it's in Dublin so I'm pretty sure you'll find someone nearer. AFAIK he just deals in DPFs already removed from cars, that are sent in from garages. The process was explained to me (albeit 2nd hand) a couple of years ago and I was driving a petrol E39 and a pre-DPF era diesel E46 at the time, so was only paying so much attention. TBH, it did sound a bit more involved than jet washers, drain pipes and a huff & a puff on the end of it :) 

 

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29 minutes ago, keliuss said:

 

Well it's in Dublin so I'm pretty sure you'll find someone nearer. AFAIK he just deals in DPFs already removed from cars, that are sent in from garages. The process was explained to me (albeit 2nd hand) a couple of years ago and I was driving a petrol E39 and a pre-DPF era diesel E46 at the time, so was only paying so much attention. TBH, it did sound a bit more involved than jet washers, drain pipes and a huff & a puff on the end of it :) 

 

I have been trying to find a hydro cleaning place near me but no luck :(

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Thought it's about time I update this...

 

I took it back to the mapper, who redid the ECU remap from scratch. He explained when he deleted the EGR, he also copied across some of the EGR changes in the original (rubbish) DPF-delete map. He wasn't sure why it had been done but figured it was there for a reason. Ultimately something in the EGR delete was causing it to try to regen, then fail. 20 seconds later it would start to try and regen again, etc.  The car is now effectively a standard stage 1 remap, with the EGR and DPF functions all enabled.

As soon as we took it out to test, it entered regen and this time kept going, all the way up to 630C. No funny yo-yo temp behaviour - the regen stayed active and the temp stayed high for ~10 minutes. I had clearly caused the DPF to get rather full during my testing as I could visually see the back-pressure reducing on the live data as soon as the temp was over 600C. Back-pressure and soot mass dropped quickly, and it finished the DPF regen cycle with soot mass at 0g. The car felt appreciably livelier and quicker.

 

That's the good news. The car now regenerates as I would expect, ultimately the prior behaviour was down to the EGR hysteresis map messing up the regeneration cycle. I've also now reinstated the swirl flaps with the upgraded aftermarket refurbishment from germany.

 

I'm finding that the car is going through a regeneration cycle every 60-90 miles. It will regenerate when soot mass reaches ~43g. It completes a regen when soot mass reaches <2g, or if it times-out (30 minutes or so?). I've noticed that very quickly after regenerating, the soot mass climbs back up to 30g or so - in a little over 8 miles of moderate speed driving. It then climbs more slowly up to 43g over the next 40+ miles, whereupon it goes through another regen cycle. 

 

I've noticed it is very hard to see 'true' back-pressure readings, as the pressure seems dependent on RPM/engine-speed, throttle load, DPF temperature and crucially the EGR position. More EGR = lower seen pressure. After a regen and with the car cold at idle, I see ~8mbar. When warm this is ~11-12mbar. When approaching regen level it is 16-20mbar. The number I now use as a reference is at a steady 75mph indicated on a level road with cruise enabled, with EGR at ~58%, back-pressure is ~48mbar after a regen and the DPF has cooled back to a normal ~300C. By watching back-pressure under these conditions I can get a sense of how clean the DPF really is, rather than the estimated soot mass which seems quite artificial.

 

I think my professionally cleaned DPF still has a fair bit of ash in it, so the back-pressure is higher than a truly clean one even after a successful regen. The ECU estimate for soot during regen  runs down to 0 regardless of actual pressure (i.e. some kind of expected behaviour curve). Once the regen is complete, the car restimates the soot mass from actual data, and quickly ramps up to around 30g. From then on the increase in soot mass is 'real' as mileage increases. The 'ash mass' value is very very slowly increasing with mileage. It is currently about 3.6g. It seems to increase about 0.2-0.25g per forced regen request (the value jumps as soon as the ECU has accepted the request, so if it was already in a regen or has just finished one, the request gets rejected). It increases naturally at around 0.01g per 70-100 miles. I'm assuming that, simplistically, the ECU estimates mass from all the real data it can read, then subtracts ash mass to give you soot mass.

 

I've also noticed if the regen gets interrupted, for instance because of slow traffic, the ECU can abandon the regen if the soot mass has dropped below ~20g. The regen requested indicator stays lit but the car stops the active regen and won't do another one until soot goes back up to the ~43g mark. Crucially the 'distance since last successful regen' value does not reset.

 

It's difficult to tell, but anecdotally the swirl flaps have made little difference. Initially I thought I could detect slightly better low-down torque but I now wonder if this was a placebo.

 

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@Adamantia

Great detailed post there, many thanks. I've been monitoring a lot of data on my frequent regens too. 

I've also observed the soot mass climb back up very quickly after a full regen. But not always. It's behaviour is not consistent so still stifles me. 

I've not factored the EGR into my observations so will start looking at that too.

All your observations concur with my own findings.

What are you using for live data? 

 

Keliuss 

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Yes you were! In hindsight it was obvious, but at least it's done!

 

I'm using the B-Tool Expert app on android with a cheap Elm327 bluetooth adapter, after trying the Lite version (expert was only £10). It is very good for what I'm using it for. You can set what parameters to display, can log data, can force a regen and reset the DPF (i.e. if you replace the DPF). It seems to match up data wise with what I see in ISTA but it's much easier to use and crucially can display all the desired data on the same page/screen, plus some of the variables are not visible at all in ISTA. It only seems to be for the M47 and M57 diesels though

 

Everyone else seems to use Carly but it's hideously expensive and I don't like the approach taken towards early adopters. The B-Tool is much more limited but perfect for diagnosing DPF, I use NCSExpert to code so no need for Carly for that.

 

I have noticed some inconsistency with the estimated soot mass. It's almost as if the ECU starts a regen and just expects the soot to decrease once temp reaches over 600C. If the temp comes down because of slowing down or traffic, the soot estimate still decreases over time until the regen stops. I think some of the time the DPF isn't as clean as it could be after a regen cycle because of this, and thus the soot mass increases much more quickly after the cycle ends. I've also found that the type of driving after a regen can determine how quickly the estimate rises back up. Steady dual-carriageway driving means the estimate increases much more slowly than if I am on a B road or coasting for extended time. Also, the estimate will only start increasing after a cold-start once the coolant temp is above ~50C.

 

If you accelerate rapidly, or drive fast for a short period, the estimate rises very quickly. I think this is more down to the fact the EGR closes as soon as you do this, and this increases the exhaust backpressure rather than the soot level actually increasing. If you then go back to more sedate driving often the soot value will decrease back a bit.

 

 

 

 

 

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1 hour ago, Adamantia said:

Yes you were! In hindsight it was obvious, but at least it's done!

 

I'm using the B-Tool Expert app on android with a cheap Elm327 bluetooth adapter, after trying the Lite version (expert was only £10). It is very good for what I'm using it for. You can set what parameters to display, can log data, can force a regen and reset the DPF (i.e. if you replace the DPF). It seems to match up data wise with what I see in ISTA but it's much easier to use and crucially can display all the desired data on the same page/screen, plus some of the variables are not visible at all in ISTA. It only seems to be for the M47 and M57 diesels though

 

Everyone else seems to use Carly but it's hideously expensive and I don't like the approach taken towards early adopters. The B-Tool is much more limited but perfect for diagnosing DPF, I use NCSExpert to code so no need for Carly for that.

 

I have noticed some inconsistency with the estimated soot mass. It's almost as if the ECU starts a regen and just expects the soot to decrease once temp reaches over 600C. If the temp comes down because of slowing down or traffic, the soot estimate still decreases over time until the regen stops. I think some of the time the DPF isn't as clean as it could be after a regen cycle because of this, and thus the soot mass increases much more quickly after the cycle ends. I've also found that the type of driving after a regen can determine how quickly the estimate rises back up. Steady dual-carriageway driving means the estimate increases much more slowly than if I am on a B road or coasting for extended time. Also, the estimate will only start increasing after a cold-start once the coolant temp is above ~50C.

 

If you accelerate rapidly, or drive fast for a short period, the estimate rises very quickly. I think this is more down to the fact the EGR closes as soon as you do this, and this increases the exhaust backpressure rather than the soot level actually increasing. If you then go back to more sedate driving often the soot value will decrease back a bit.

 

 

 

 

 

Great, going to try that B-Tool app. Sounds very interesting, it also states it works on N47 / M47 / N57 / M57 so good for me (N47). Sounds like it will take a lot of the pain out of my current Torque app setup using custom PIDs. 

Thanks again.

 

Keliuss

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2 hours ago, Adamantia said:

Yes you were! In hindsight it was obvious, but at least it's done!

 

I'm using the B-Tool Expert app on android with a cheap Elm327 bluetooth adapter, after trying the Lite version (expert was only £10). It is very good for what I'm using it for. You can set what parameters to display, can log data, can force a regen and reset the DPF (i.e. if you replace the DPF). It seems to match up data wise with what I see in ISTA but it's much easier to use and crucially can display all the desired data on the same page/screen, plus some of the variables are not visible at all in ISTA. It only seems to be for the M47 and M57 diesels though

 

Everyone else seems to use Carly but it's hideously expensive and I don't like the approach taken towards early adopters. The B-Tool is much more limited but perfect for diagnosing DPF, I use NCSExpert to code so no need for Carly for that.

 

I have noticed some inconsistency with the estimated soot mass. It's almost as if the ECU starts a regen and just expects the soot to decrease once temp reaches over 600C. If the temp comes down because of slowing down or traffic, the soot estimate still decreases over time until the regen stops. I think some of the time the DPF isn't as clean as it could be after a regen cycle because of this, and thus the soot mass increases much more quickly after the cycle ends. I've also found that the type of driving after a regen can determine how quickly the estimate rises back up. Steady dual-carriageway driving means the estimate increases much more slowly than if I am on a B road or coasting for extended time. Also, the estimate will only start increasing after a cold-start once the coolant temp is above ~50C.

 

If you accelerate rapidly, or drive fast for a short period, the estimate rises very quickly. I think this is more down to the fact the EGR closes as soon as you do this, and this increases the exhaust backpressure rather than the soot level actually increasing. If you then go back to more sedate driving often the soot value will decrease back a bit.

 

 

 

 

 

Is yours pre LCI or LCI?

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2 hours ago, Adamantia said:

LCI - so the has the M57N2 and thus the DPF is situated immediately downstream from the turbo, beside the cylinder block. A pain to get in/out!

Yes I have had mine out twice now, only reason I asked was the display of ash and soot content as ISTA doesn't show it unless it is part of a fault log for the LCI 535d.

 

*edit.

 

Contemplating another gallon of Wynns off car DPF cleaner for the DPF I got last week, this one's only got 75k on it.

Edited by GoNz0

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:(

B-Tool app not working with my cheap elm327 Bluetooth adapter. Still waiting on my cheap WiFi one. Hopefully better luck with that. 

@Adamantia Which type of "cheap" one do you have? 

 

Keliuss 

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Just to add to this, my lci 530d was doing regens every 70-90 miles, it was really annoying me. 

What I hadn't considered was the fact I was using a DTUK CRD+ Tuning box, now, whether a box or a remap what we know we are doing is increasing the fuelling which in turn increases the amount of exhaust soot, which obviously fills the DPF up quicker. 

 

I removed the tuning box and within a week my car actually felt livlier, not as quick but just more better, and now I am only getting it regen every few hundred miles or so, it does it quickly for 10 mins or so and then nothing for another few hundred miles. 

 

I don't think these cars like being mapped as they get older. 

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When you are requesting DPF Regen or Replacement DPF on the right hand side of the ista it has description tab with all the technical stuff on it. It says the EGR together with Throttle valve/butterfly valve can increase the exhaust temperature by up to 140°C (if memory serves me correctly) 

If the EGR is blanked or the butterfly valve doesn't work or there is a glow plug/controller fault or thermostat fault or other things that might be going bad fault then DPF clogging up is inevitable. Most of the times it is a underlying issue. 

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