DPF issues after Adblue delete

[dan1w]

Hi guys,

I had a 'reductant pressure too low' fault with the adblue system that was diagnosed as a faulty pump. Specialist wanted 1k to change the pump which given the age and mileage of the car wasn't feasible, I would have tried to fit a used one and get it coded myself but had no time and needed transport so went with an adblue software delete from the specialist. The car is a 2015 A4 2.0 TDI Ultra.

Confirmed with their tech before work was carried out that it wouldn't interfere with DPF regens as a DPF 'below efficiency' fault had come up after the adblue fault and I'd assumed this was as it wasn't regening while the adblue fault was present.

Day after I got the car back the DPF 'check owners manual' warning came up. The vast majority of my driving is motorway anyway but I drove about 60 miles keeping the revs above 2k. No joy so I then drove about 40 miles in 4th gear the day after. No joy with that either and the flashing coil and engine light came on.

I've got an OBDeleven and tried to force a regen both standing and driving and had no luck. The measured soot value was about 30 when I first checked it and was 48 last night. I figured the car might be blocking the regen because the soot value is now so high so I zeroed it and tried again and still no luck, after 40 miles the 'check owners manual' is back. If I monitor measured soot whilst driving I can literally see it ticking up about 3g in 30 miles.

I'm wishing now I'd not got the delete and it seems like it's blocking the regeneration. I'm going to call the specialist today and see what he says.

Any ideas here would be much appreciated. Has anyone had any issues with DPF regens after an adblue delete? Anyone know a way I can check for certain whether the delete is blocking the regens?

The only force regen instructions for OBDeleven I can find seem a bit outdated so maybe there's a new procedure for the latest app version?

I imagine with the punishment I've now given the DPF it's going to have to come out, how involved is that on the 2.0l TDI Ultra?

Cheers guys,

Dan

 

[Darren92]

They're all interlinked, can't delete one and not do the other.
Not getting at you in any way but these easy get-outs cause more problems than they're worth.

 

[Dippy]

Yes and no. DPF is for particle removal but AdBlue is to lower nitrogen oxides. The tech was technically correct that AdBlue delete wouldn't interfere with DPF regeneration because that is a function to recover the DPF capacity, totally separate from what the AdBlue system does. However it sounds like their "software delete" is too basic, just removing the AdBlue functionality but not dealing with any impact that it would have - in other words they may have overlooked something specific to your car (or maybe they don't really know what they are doing).

What's the legal situation? I read somewhere that the Government was going to tighten up on all this activity and make it clearly illegal.

 

[pelhamsdetailing]

Something hasn't been mapped correctly, so it's causing your DPF to not regen anymore. If there is an underlying issue that isn't related to the software changes the company made, like an exhaust gas temperature sensor not registering correct readings, or a DPF pressure sensor not operating as it should, then these will cause the DPF regen to not take place. These two examples typically lead to their own specific fault code being stored in the ECU, leading to an engine light.

If it were me, take it back to the people who messed around with the software in the first place and request they correct the problem they may have created. However, if they refuse or cannot fix it, you'll need to contact a reputable company who knows what they are doing. The sooner the better.

I hope it gets sorted