New NCT rules (OBD scanning) and DPF removal

Just1more

Hi all,

Friend of mine has a dilemma on his hands.

His 2010 astra diesel has broken down and his mechanic is telling him that someone previously working on his car broke a sensor on the DPF and glued it back in place. Because the sensor was broken the DPF hasn't done a regeneration in ages and it's now totally blocked to the point where the engine can barely start and conks straight away. He doesn't have the car long and bought it through a private sale so no recourse available there.

Mechanic initially said he can get a guy to clean it, they've come back and said its beyond cleaning.

His mechanic has offered DPF removal for 500 quid, he said he will reprogram the ECU so it doesn't throw a light on the dashboard etc. The other option is replacing it altogether for approx 1500 quid which my friend can't afford. The mechanic has said that he won't find a 2nd hand one worth installing - not sure how true that is but he's been recommended this guy by a friend and trusts his word. I'm assuming they open the unit, cut out the insides and reinstall the shell in the exhaust line so it's not obvious it's gone.

Does anyone know whether this will be spotted by the NCT now that they check the OBD during the test? Has anyone here passed the new test with a DPF delete or failed for this reason?

As an aside this has made me very glad to own a nissan leaf 😅

User1998

If the job is done properly and the DPF coded out then it will have no problem passing the NCT. The mechanic should hollow out the DPF and leave the external structure in place to make it look like it hasn’t been tampered with.

Dont mind all the stupid comments your going to get on here from the DPF Police

zg3409

In USA this has been the case for years and some people use a fake odb port that says all ok, while real odb port is hidden...

Whocare

As of now nct don't check for engine fault codes. Only braking system /airbag codes

Vowel Movement

Mine was in today, engine light on and code for crank position sensor. Still passed. Car was diesel also.

Whocare

https://www.boards.ie/discussion/comment/118999139#Comment_118999139

Strange as only month ago my dad car failed because engine light on ie had do smoke test again (egr fault

But under obd2 it only had abs fault and that was pass advisory (abs light is not on and is still working if you hit brakes hard

Vowel Movement

https://www.boards.ie/discussion/comment/119004011#Comment_119004011

Yeah, i was sure it was going to fail but pleasantly supprised.

Immortal Starlight

Does anyone know if they check for old stored fault codes for drivetrain faults in 4 wheel drive cars?

User1998

Doesn’t matter because no matter how many fault codes you have its just an advisory

Immortal Starlight

That’s good news. I thought they had changed it from fail advisory in 2021 to fail in 2022.

Dr_Colossus

https://www.boards.ie/discussion/comment/119004691#Comment_119004691

Not DPF related but my car failed the NCT in 2021 due to an "Anti Skid Service Required" fault code showing so the type of fault does matter. No impact to ABS or braking performance test and fault was due to a bad segment within the steering angle sensor.

vandriver

I got an advisory for a stored low tyre pressure warning code.

Codpeas

https://www.boards.ie/discussion/comment/119004372#Comment_119004372

According to the NCT test procedure docs it should have failed. The engine light being on is one of the pre-checks before carrying out the emissions testing and they are not supposed to proceed if any of the pre-checks fail.

kirving

https://www.boards.ie/discussion/comment/119009328#Comment_119009328

The Active Yaw Control component of Volvo's DSTC system will engage the ABS pump to individually brake each wheel to help steer the car. eg: your turn hard right, front right is overloaded and skids, the gyro and accelerometers notice this, the ABS pump brakes the front right wheel only to spin the car clockwise. So an issue with the steering angle sensor may be thrown up as "anti skid service required".

bcklschaps

Sorry to bring up an old thread.

I have a persistent problem with DPF (diesel car) getting clogged up (my mileage is low and mostly short journeys) was considering getting DPF removed entirely (inside of DPF unit emptied out and Ecu reprogrammed) quoted €300 for the job. Worried about the NCT though... from earlier comments, am I to understand that as long as ECU reprogrammed, all will be grand?

https://www.boards.ie/discussion/comment/122024967#Comment_122024967

It should be a fail, but whether they detect the missing DPF is another matter. They are checking for safety related fault codes and the absence of a DPF is not a fault as such.

However the issue is that a DPF should be good for around 150k miles so if it is giving issues prematurely it is most likely an upstream problem with the engine. If he goes in for the test and there is black smoke coming out of the exhaust it's a sure sign that the DPF is gone and he will then fail you. So he needs to do a full diagnostic to attempt to find out what the underlying cause of the premature blocking is.

prawnsambo

https://www.boards.ie/discussion/comment/122024967#Comment_122024967

Have you tried doing a "motorway service" on it? Take it out on the nearest motorway and run it for an hour or so (they say 20-30 minutes, so an hour would be more than enough) at 120kph. DPF regen needs the engine hot to burn off the soot in the DPF. A low mileage car that only does short trips is a recipe for a clogged DPF. But it shouldn't be too bad with the low mileage. If you've already done this, then the other option (besides getting it hollowed) is to get it cleaned professionally. Good few places doing this for a fraction of the cost of replacement.

bcklschaps

https://www.boards.ie/discussion/comment/122025040#Comment_122025040

Mileage on the clock is just shy of 150k mls. 2012 car. Have only owned the car since 2021. Have had the car into main dealer twice in those 3 years to get the DPF cleaned. It's a €500 job. Main dealer didn't detect any other problems besides my driving habits.

prawnsambo

https://www.boards.ie/discussion/comment/122025107#Comment_122025107

There are lots of independent operations that will do it for less than that. Or at least that's what they claim. Google "cost of DPF cleaning" to see a selection, some starting as low as €170.

Edit: Another cause of this besides driving habits, is the condition of the glow plugs. Apparently these need to be working well to carry out a proper regen. They might be fine for starting the car, but not good enough for the regen. And if your car is a bit lumpy starting up, it will most definitely be a contributing factor.

The issue with DPFs is not the soot which can always be cleaned, but the slow steady accumulation of ash which is far more difficult to remove. This is why they are only specified for around 150k miles after which they cannot be cleaned adequately. The issue comes in if they have been placed in such a location that it becomes necessary to drop the engine to remove them and this is where the significant costs accumulate.

prawnsambo

https://www.boards.ie/discussion/comment/122025165#Comment_122025165

Yeah. Not all the cleaning operations guarantee ash removal. But some do. Depends on the method used. Dropping the engine would be a major pain alright, but I don't think that's common. Most DPFs are well after the exhaust manifold and removable from underneath the car.

https://www.boards.ie/discussion/comment/122025221#Comment_122025221

As far as I know all the ash removing processes require an oven bake which necessitates the removal of the DPF.

From personal experience my mitsubishi lancer has the dpf on the firewall bulkhead with no access from top or bottom. The only way to get at it is to drop the engine. Really bad design for a service part. Any sensible engineer would never do such a thing.

prawnsambo

https://www.boards.ie/discussion/comment/122025552#Comment_122025552

Yeah, I think most (if not all) of the cleaning methods require removal. I think that crowd I linked just collect, clean and return your DPF, removing and replacing are on you or your local mechanic.

That is a pain wrt your car. Somebody wasn't thinking when they designed that. The good news for the op is that the Astra DPF is relatively easily removed and replaced. There's a YT video of a guy doing it himself in his driveway.

User1998

https://www.boards.ie/discussion/comment/122026180#Comment_122026180

If you have the right diagnostic software you can put some DPF cleaner into the engine and do a forced regen without removing the DPF. I guess that counts as cleaning.

mondeoman72

The exhaust can be removed, then the top of exhaust gets cut open and contents removed. Then welded up and ECU remapped. The weld is on the top of the exhaust and cannot be seen from underneath

If done properly, i still passes NCT.

https://www.boards.ie/discussion/comment/122027157#Comment_122027157

Non of the off the shelf cleaners will deal with the ash build up so only really suitable for people who have fragged their DPF with excessive short journeys.

BlakeS94

I've had my DPF gutted over a year ago, passed NCT in February no bother.

If you're going down the delete route get it done right. Not just a fella with an angle grinder and a chisel in his back garden.

kaahooters

so, were alowed talk aboutDPF removal now? thought that was "fround upon"

cpoh1

https://www.boards.ie/discussion/comment/122027157#Comment_122027157

Thats all a main dealer will ever do really, force a regen. They wont remove a DPF and clear the ash which is likely causing the problem here.

Best bet to get the DPF removed and take it to a respected 3rd party cleaner to get it properly cleaned.

mikeecho

Also if ash build up is a common occurrence, see if HVO100 fuel is available in your area

It creates practically no soot.