Force an OPF regen

[fletch555]

Hey
Is there any way to force an OPF/GPF regen using ODB11?

I don't understand how it decides to do a regen. Last weekend I did 2, 2hr drives taking in motorway for about an hr and fast N roads the other times, so the engine was well up to temperature and would have been a perfect time to do a regen. Today, the car decides to do a regen but I don't have a plan to do any long journeys planned for another few weeks so I'll probably have to endure a good few horrible/jerky/inefficient drives while the OPF regens.

In future, I'd like to be able to let car get up to temperature and then start a regen (on a long journey)

[S_94]

This happens around every 3-6 months on my GTI. Best advice I can give is, get the car up to temperature, whack it in Sport mode, and give it a really good blast (safely) on some 60/70 roads. Do this a couple of times and it should sort itself out.

[SRGTD]

When I had my GTI+, the process I used for helping to keep the GPF clear was to use the car’s engine braking when the engine was up to optimum operating temperature. This was recommended by @monkeyhanger (his wife owned a GPF equipped Polo GTI+). Quote from @monkeyhanger’s post on the forum from a few years ago;

‘Engine braking pulls air through the engine that isn’t used in combustion of fuel ("motoring") and ends up in the exhaust where the oxygen is available to burn off the soot as CO2.

I used to do this periodically on longer journeys - when at cruising speed, dropped a gear to increase the engine rpm’s and then let the car decelerate under its own steam to draw air into the exhaust, accelerate back up to cruising speed and then repeat the process a few times. This is actually the officially recommended process for clearing a blocked GPF that’s quoted in some Seat Leon owners manuals.

Additionally, when I was aware my car was performing a GPF regen and I was getting towards the end of my journey, I’ll extend the journey a few minutes / miles if possible so that the process could complete. If not, the regen process would recommence on the next (and subsequent) ignition cycle(s) until it had finished. Normally with my car, it took around 25-30 minutes for an active / forced GPF process to run; after that, everything was back to normal again.

[fletch555]

Thanks for the advice re using the engine braking SRGTD, I will try that in future. I would just love for a way to know when my car is coming up to needing a regen and if I could initiate it myself as it always seems to happen at awkward times for me and I absolutely hate driving it while it's regenning.

[OomStu_ZA]

I'm so grateful we don't have GPF issues here in South Africa because they not equipped from factory. That said we do still suffer carbonised valves here due to fuel quality so need them cleaned every 50 000km.

[TheRacingRat]

My Polo GTI 2020 is on 27K and not had single regen that i'm aware of. I'm starting to wonder if they forgot to put one on

[SRGTD]

My Polo GTI 2020 is on 27K and not had single regen that i'm aware of. I'm starting to wonder if they forgot to put one on

There are two types of regen; active(forced) and passive. The mix of journey types you drive will be a significant factor in which you’re likely to experience.

If you’re driving a high proportion of longer journeys when the engine’s quickly up to optimum temperature, your GPF / OPF will collect less particulate matter than someone driving short(er) journeys on a cold engine. Additionally, the exhaust temperature should be sufficiently high for accumulated particulate matter to be neutralised passively and you’re very unlikely to be aware of this happening.

It’s a high proportion of shorter journeys on a cold engine that forces the car to initiate an active GPF / OPF regeneration with many / all of the tell tale signs;

• Louder exhaust note

• Significantly increased fuel consumption

• Slight hesitancy / lumpiness to the engine at slower speeds

• Slight hesitancy to accelerate

• Stop start function doesn’t operate

• Engine fan running continuously

With short journeys on a cold engine, the exhaust temperature doesn’t get high enough to passively neutralise accumulated particulate matter, and when this particulate matter reaches a predetermined level, the car will go into active regeneration mode.

So I’d say it’s extremely unlikely VW forgot to fit a GPF / OPF to your car. The fact you’ve not noticed any regenerations happening is probably down to the mix of journey types you drive.

[grazuncle2]

My Polo GTI 2020 is on 27K and not had single regen that i'm aware of. I'm starting to wonder if they forgot to put one on

Same here.. Apart from a fault with the car once and engine revving at 1400 at idle for a few day and fixed 'apparently' with a forced regen by the VW garage without charging me (despite warning me of a £150 charge if no faults found) and a software upgrade.. I know what I think

I run, mostly, short shopping trips. only did 2,000 mile last year. and OBD11 reports very little change in particulates... did a good run last week on motorway and the particulates figure hardly budged

I use engine overrun and engine braking a lot.. perhaps that helps?

[lancslad1985]

I remember reading an article a couple of years back on gpfs and it basically said they cleaned themselves on engine braking and overruns. They differ in how they work to a dpf, which needs long periods at a constant temperature to clean themselves.

In my gtis I used to occasionally get up to 70 in a low gear then let it ease down to 50 a few times whilst holding that gear and I never had a single regen despite doing 12k miles a year.

[SRGTD]

I remember reading an article a couple of years back on gpfs and it basically said they cleaned themselves on engine braking and overruns. They differ in how they work to a dpf, which needs long periods at a constant temperature to clean themselves.

In my gtis I used to occasionally get up to 70 in a low gear then let it ease down to 50 a few times whilst holding that gear and I never had a single regen despite doing 12k miles a year.

I’d hazard a guess that you were also driving predominantly longer journeys rather than lots of short journeys. Assuming yes, then with a high proportion of long journeys the exhaust temp gets hot enough to passively neutralise any accumulated particulate matter in the GPF, reducing - or even eliminating - the need for the car to initiate the forced GPF regen process.