DPF Issues?

Faults and Technical chat for the Mazda CX-3
aldaman
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Joined: Tue Aug 28, 2018 9:29 am

Post by aldaman »

It’s definitely doing a regen as I shut it off with the fan running the other day and istop wasn’t functioning.

When I drove the car the next day it started regenning again as soon as the engine was ready.

sophiesmith
Posts: 1
Joined: Thu Aug 13, 2020 5:21 pm

Post by sophiesmith »

I have recently purchased a CX-3 1.5D and was wondering if someone could help. I usually drive 70 miles a day (motorway all the way) for work but due to the COVID lockdown I have been working from home so mainly just doing short distance (20/30 minute trips) to the supermarkets and to visit family members recently. I have still been going to work approximately once a week however on my way home from work the DPF light started flashing. I got in touch with the dealer I bought the car from as i have only had it 4 weeks and they said I must have turned off the engine whilst it was doing a ‘regen’ so I had to take it to the dealer for them to process an regen manually. can anyone advise me how to identify when the car is doing a regeneration to prevent this from occurring again!
Strangways
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Post by Strangways »

I am a little bit at a loss as to why anybody would buy a diesel (or sell one nowadays), apart from people who do very long motorway journeys and a very high mileage. Even then, they must know about the pollution it causes and feel that the personal cost saving outweighs pollution cost. I guess the same can be said for petrol against electric vehicles, so I am as bad in this respect. So does purchase cost take priority over running costs and the environment?
2019 CX-3 2.0 Sport Nav+ Automatic in ETERNAL BLUE
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st3v3cx-3
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Post by st3v3cx-3 »

Deleted my comment - I was guessing and wrongly it seems. The jtonline reply below is far more comprehensive and from someone owning a diesel so I bow to his knowledge on the whole topic.
Last edited by st3v3cx-3 on Fri Aug 14, 2020 12:21 pm, edited 1 time in total.
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jtonline
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Post by jtonline »

sophiesmith wrote: Thu Aug 13, 2020 5:27 pm ...on my way home from work the DPF light started flashing. I got in touch with the dealer I bought the car from as i have only had it 4 weeks and they said I must have turned off the engine whilst it was doing a ‘regen’ so I had to take it to the dealer for them to process an regen manually. can anyone advise me how to identify when the car is doing a regeneration to prevent this from occurring again!

Turning your engine off whilst an active DPF regeneration is happening is not a problem. I've done it on occassions - I'm not going to be late for work because I had to continue driving for 20 mins until the regen completed! The garage that told you it's the cause of your DPF warning light is talking nonsense, are they an authorised Mazda dealer? My regular commute 5 days a week is a 30 minute journey on A and B roads.

Repeatedly stopping regens. before they complete can cause your oil level to rise above full due to diesel dilution, and you should keep an eye on the dipstick level to make sure it doesn't go above the X mark. If it reaches the X mark before a service is due (scheduled service intervals are every 12,500 miles or 12 months, whichever comes first) you will need to have the oil & oil filter changed using the correct ACEA C3 oil.

If the DPF comes on solid, it indicates that the particulate matter (PM) in the DPF cannot be removed automatically as usual, if the car is driven at, ideally, 2,000rpm (book says over 12km/h (12.5mph)) for 20 mins or so then the PM should be removed and the light goes out. If, however, the car is continually driven with the DPF light on, the PM increases and the indicator light may start flashing. If the light is flashing, have the car inspected immediately at a Mazda authorised repairer as it's probably a blocked filter or a fault. It is possible for them to instigate a manual active regeneration process which may burn off excess PM in the DPF.

Why has the DPF filled-up? Has the correct engine oil been used? Is there a fault elsewhere in the vehicle? Was that why the previous owner sold it?

There is no indicator light to show the car is doing a regen. (it's not the DPF light as that only comes on when there's a problem). If you have the i-stop economy page showing on the infotainment screen, an indication that a regen. is happening is that the blue halo around the engine icon goes out, but this is not a reliable way of telling as it goes off for other reasons too. Also, if you have the mpg showing on the instrument cluster you should see a sharp decrease in mpg for the duration of the regen.
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