Hey guys

Apologies as I know there are a few DPF posts on here but I haven't been able to conclusively find one for our situation... In Nov last year the wife and I bought a 2015 Mazda 3 2.2 diesel from an independent garage.

Shortly after we had the DPF light come on steady which was the switched off after a bit of a drive at high revs as google appeared to recommend. In Jan of this year the dpf light came back on but flashing, this time google and the handbook seemed to show take it to a garage for fixing rather than the constant drive. I booked it in at Mazda, they checked it over, changed the oil and reset the oil change counter charging us about £200 for the privilege as I needed it done urgently, which resolved the issue. Allegedly they had a look over the DPF, had plugged it in etc and there was no evidence to show that there was anything more sinister than the oil change being needed.

Now though, we are just two months down the line and the dpf light has just popped up flashing again unfortunately. Does anyone have any ideas on where to go from here? Obviously I'm conscious I may need to go to Mazda again but on the basis that it was just a temporary fix last time and inevitable this will be much more expensive again, I was hoping someone had an idea of what was going on!

Cheers

edit: this is also directly following a long haul drive at the weekend so I would have thought it would have regenned then???? The wife goes to work not ages away but it does include about a 10 mile stint on a dual carriageway.

 

Without getting it scanned for fault codes, you can but guess.

 

I had it scanned when it went in for the oil change which booted out the code P243c, apparently

 

Unfortunately this still appears to be an issue. The code (was) I’m told P243C. I found this helpful manual on it: id0102j5585900.html

the light has been turned out and the car is currently not returning any error codes. However, the car still is regenerating far too often at around once per 50 (or even less) miles, with almost all of the miles being motorway driving.

I had a friend who’s a technician look at it, did some tests etc and he thought the exhaust pressure sensor was failing due to a low return volt amount into the sensor. He performed another test from the sensor to the injectors which I’m told should give a reading as to whether or not the dpf is actually blocked, which he confirmed it wasn’t on the basis of the reading given out.

The sensor has been replaced but is still regenerating often.

The engine appears to perform absolutely fine, no limp mode, idles fine, performance fine. MPG is absolutely fine too until it regens which puts it in the bin, obviously. For example it is usually around 50-55mpg it seems for a slight mix of motorway and town driving, then regen kicks in and the average of course plummets down to about 41mpg.

I’m going to attempt to reset the ECU tonight but I’m expecting that is unlikely to do anything.

I realise it’s rare but I’m leaning towards something more like electrical like a pcm fault, considering my understanding is that fuel injectors or egr valve would cause adverse mpg consistently, rather than normal mpg, normal mpg, normal mpg and then plummets due to a regen?

apologies on mobile so I doubt this is formatted amazingly!

if anyone has ideas or can help I’d love you long time