Turbo/exhaust pressure pipe sensor fault

[Frane Selak]

This is just a general question really, I've had a quick look at a car for someone I know that they have just bought (knowingly) with a fault. Car is a 2015 Mazda CX5 2.2 diesel, the fault code relates to the part in the post heading, its not the DPF differential sensor, its the other one that measures the exhaust pressure. When I had a quick look the supply pipe to the sensor is blocked solid just like they do on quite a few different cars apparently, certainly it seems a common problem on various cars that I watch being repaired/diagnosed on YouTube.

I did have a quick go with a piece of wire to unblock it but its solid so he will have to go elsewhere, I don't want to get too involved with it, certainly not this weather. Anyway I noticed that the exhaust is also full of soot as well at the tail pipe, I would expect it to be relatively clean, think the cars done about 80k or so. The EGR was also unplugged when we had a look.

So with all that in mind am I right in saying the DPF is either cracked or been removed altogether and mapped out and because of this the EGR valve is jammed with soot and has also probably been mapped out (no EGR code despite being unplugged) and that's why the sensor tube is also blocked. People don't sell cars cheap that only need a £5 sensor.

Just out of curiosity do those exhaust pressure tubes connect to the exhaust before or after the DPF, I would have thought it made sense to connect them after so they don't get jammed with soot like the EGR's do being so thin.

Cheers.

[normalbloke]

Walk away….

[Frane Selak]

Oh I'm not getting involved, I've got far too much going on anyway. I was just curious if I was right or not as that's what I told him.

[E-bmw]

Rather than fix what could have been a simple fault a previous owner has proper fked it.

[Frane Selak]

I reckon they have, apparently its had new injectors and a new turbo plus other work recently at a cost of £2K and you can see they do look pretty new. would be funny if all the faults they "rectified" were really caused just by that block pipe. I didn't mind helping for an hour or so just so he knew where he stood with it really really.

It does annoy me a bit to be honest, I don't want to blow my own trumpet but I can do a fair bit of different stuff, maybe not to expert levels on every subject but enough to get by in most cases and because of that quite a few people mither me quite a lot to "help them out" with different stuff, not particularly because they want stuff doing for nothing but because the alternative is either not being able to find anyone to do it or if they do find someone the cost is so prohibitive that its not worth doing. People would have me doing stuff every Saturday and Sunday if I let them.

[stevemcs]

If it’s the pipe I’m thinking it is then in order to change it you may have to remove the turbo to fit it as it’s hidden behind it.

[Frane Selak]

stevemcs said:

If it s the pipe I m thinking it is then in order to change it you may have to remove the turbo to fit it as it s hidden behind it.

Yes I've seen the videos of it, some youtube mechanics have had success with some DPF cleaner down the pipe and piano wire in a drill to bore it our, Jimmy O'reiley is one of them and he does it fairly often with Renault Traffics that have that problem but this pipe feels really solidly blocked, like its been there for ages.

Other video's I've watched show them heating the metal tube up with a blow torch and then blowing it out with compressed air but to get access to the metal pipe it means taking the rocker cover off which obviously means all the injectors out and they also took the EGR valve off the side so it had somewhere to blow it out again.

Imagine doing all that as a favour and then the car doesn't start again when you put it all back together or you melt something vital with the torch, who's problem would it be and its a problem I could do without at the moment. I fixed a bad oil leak on my mates BMW a while ago and when I put it back together it was in limp mode and threw an intake air leak error, even though my smoke machine didn't show any air leaks I just couldn't get the code to clear, it took ages and lots of research to find out that before the code will clear you have to run an air leak test in the diagnostic settings and that bit is hidden deep inside the software, once run I was able to clear the code and it run perfectly. But there was a stage of me thinking I'm going to have to pay for a garage to do this now, all for a favour.

[stevemcs]

While the pipe gets blocked, so does the manifold, the 1.5 Nissan you can do with the cable but the Mazda you would struggle with due to its shape