Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen?

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Mon 19 Oct 2020 20:02
Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen? - BobsyourUncle

So a couple of days ago I get the dreaded 'Soot Accumulation in DPF Too High' message on my 6, which has just had it's 5th birthday and done 40k. Following Mazda's helpful guidance, off for a run down the M23 I go, keeps revs between 2.5-3k. Halfway back the message turns into 'DPF Malfunction', so I presume this means the automatic regen failed.

I call the local Mazda garage, who inspect it (well, probably plug in their code reader and charge £120 for the privilege) and tell me that the Throttle Body needs to be replaced and a manual regen tried, but this - after already leaving me £500 odd worse off - doesn't guarantee that it'll fix the problem, and the DPF might need to be replaced anyway. I'm skeptical on whether anything more than a regen is needed - car hasn't gone into limp mode and showing no performance issues and no unusual emissions. Not sure how they've reached the conclusion that the throttle body needs replacing...

Having found the procedure for the manual regen online, I'm tempted just to do it myself. But the worrier in me is thinking that I could damage to the engine, if the DPF is completely blocked!

So my options are:

1) Perform the regen and hope for the best!

2) Get it cleaned professionally and hope that sorts it

3) Bite the bullet and let Mazda do their worst...

Any advice?

Edited by BobsyourUncle on 19/10/2020 at 20:03

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Mon 19 Oct 2020 20:50
Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen? - Sparky Mark
Don’t hold me to this but I believe the revs you are driving at to perform the Regen are too high. I have been told by various sources that the car water temperature and oil temp need to be normal then a constant 1800-2000rpm is required to instigate the regen for 20-30 miles. The engine is under too much load at the higher rpm for the regen to trigger. It’s not higher rpm is better so to speak. I would put a tank of Shell V power in and try again.
Also have you checked your oil level. If the oil is diluted with fuel from previous failed regens this could have an effect on the regen. Good luck.
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Tue 20 Oct 2020 02:44
Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen? - edlithgow

Re Also have you checked your oil level. If the oil is diluted with fuel from previous failed regens this could have an effect on the regen

How would it do that? Possibly there'll be a bit more fuel-diluted oil leaking past the rings which will over fuel the DPF? Bit surprising there's enough to make a difference, though.

Edited by edlithgow on 20/10/2020 at 12:27

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Wed 21 Oct 2020 15:29
Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen? - dieselnut

My son's Passat had exactly the same problem.

He had the DPF warning light up.

I scanned it for faults & found throttle valve malfunction.

When removed, the throttle valve was gummed up with EGR crap stopping it from operating correctly.

A clean may well have cured it, but as my son lives some way away I just fitted a new one.

Took it for a run & the DPF cleared after about 10 miles & no further problems, now my wife's car for the last 4 years.

I think the valve limits the air flow through the engine during a regen to keep the DPF temperature as high as possible.

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Wed 21 Oct 2020 18:46
Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen? - Big John

Re Also have you checked your oil level. If the oil is diluted with fuel from previous failed regens this could have an effect on the regen

How would it do that? Possibly there'll be a bit more fuel-diluted oil leaking past the rings which will over fuel the DPF? Bit surprising there's enough to make a difference, though.

Some cars/engines are more prone to this than other and the Mazda 6 diesel is one of them. Engines with wear are also suscepital to this issue.There is usually a mark on the dipstick above the normal full mark to show the danger zone. Whatever it must be remembered where sump oil level is higher because of failed regens the oil will have been diluted with diesel and have reduced lubrication qualities so should be changed ASAP.

Edited by Big John on 21/10/2020 at 18:47

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Thu 22 Oct 2020 11:35
Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen? - BobsyourUncle

So I elected to try the manual regen procedure I found on an Australian Mazda forum, which didn't actually work :( I wasn't confident it would, as it seemed too easy, and so it proved...

I called a Terraclean garage in the area, who told me that it didn't sound like the DPF was blocked at all considering there's been no effect on performance and it hasn't gone into limp - and that he didn't want to take my money on that basis! (So nice to hear an honest opinion). So I'm thinking now that it's electronic gremlins, perhaps a failed sensor somewhere?

Just to add to my woes, the boot latch seems to have failed today. Could be coincidence, but it's only been opened/closed once since being at Mazda Croydon... I won't be going anywhere near them again!

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Thu 22 Oct 2020 12:49
Mazda 6 2.2d sport (2015) - DPF Malfunction warning - worth a manual regen? - BobsyourUncle

Fixed the boot closing issue. Took everything apart and reconnected it, as any good IT Tech would do :D

Button on the fob doesn't work anymore for some reason, but at least it locks again.

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