Monitoring my DPF at altitude

[Chris Ratay]

Automatic Regeneration on my 2023 VW T6.1 in South America.

After a high altitude clog in Ecuador, I started to monitor the DPF soot levels.

I found that the VW Regen automatically kicks in when the soot reaches 30g, and burns it down to about 8.5g. Driving in the Andes, it reaches 30g every 150-180km, and at sea level it's closer to 225km cycles. With more than 35,000km driven, the van has done over 1500 auto regenerations, the majority of which I never knew were happening. If you ever smell a slight burning odor - it's happening!

The Regen itself takes anywhere from ~10-25 minutes, depending on driving conditions. Downhill or stop-and-go traffic takes about 25 minutes, while foot on the gas is closer to 10 minutes.

I've driven to nearly 5,000m in altitude, but it wasn't during a Regen. After many attempts I have confirmed the ECU doesn't allow the Auto Regenerations to kick in above 3,300m. If driving above that, I estimate I have about 50km to get lower before the soot reaches 35g and the DPF Warning Light comes on.

According to the dealer computer in Ecuador, I got to 42g before going into limp mode. (You can still drive in limp mode, but "they say" anything above 50g can only be cleaned manually.)

Since the Euro6 van is made for Europe/Australia, the 3300m attitude threshold isn't a big deal.

Fortunately after going into limp mode, the dealer's computer was able to clean it with a Forced Regen. Be sure to change the engine oil if the vehicle is not moving during the regeneration.

After the limp mode fiasco, I started monitoring my DPF using the $6 paid version of the VAG DPF app with a basic OBDII reader. My data and assumptions above are from monitoring dozens of regenerations over several months in South America.

These days I assume I can drive the T6.1 above 3300m in altitude a total of 225km between regenerations, maybe 250km if I'm lucky. This means Bolivia is not an option.

The VW recommendation to "drive at 2200-2500rpms @80kph for 25 minutes" has never initiated a Regen when I've tried. I've experienced Regens while at stop lights during rush hour traffic, so those instructions don't help me.

Here are a few screen shots to show the auto Regen in process:

1 Current soot level

2 Regen Duration (basically a timer)

3 Distance since last Regen

4 Time since last Regen

5 Oil Ash Residue - this slowly accumulates. When it gets to about 120g I'll need to have it cleaned out. With 35,000km and >15g currently on my van, it'll be a few years.

6 DPF Input/Output Temperatures - normal driving temp is 225-325C, but increases to 500-625C during the Regen process

7 Current time

8 Visual scale. When the Regen cycle finishes, it only goes down to ~28%

 

[secret lemonade drinker]

My OBD Tool can carry out DPF Regenerations.

 

[Ch1pbutty]

My OBD Tool can carry out DPF Regenerations.

Just don't do it in on your driveway; It pumps a lot of nasties out the back end. Should only really be done whilst driving so that the pollution is not concentrated to one spot. Plus you want the van in motion ideally at speed as the exhaust gets very hot during a regen so better to have some airflow to help cool it.

You shouldn’t generally need to force one, the van should take care of itself, unless you are in an extreme environment.

 

[Chris Ratay]

My OBD Tool can carry out DPF Regenerations.

Have you tried it above 3300m?

I found Carista just fools the ECU into thinking the soot is at 30g, but it doesn't solve the attitude issue

Also, Carista fails to mention A) you need an internet connection to sign into the app, and B) the bonnet needs to be opened in order for the Regen feature to start. Once it starts (yellow light) you can close the bonnet.

If using a VCDS, you need to enter the security code for the Regen feature to work

 

[Chris Ratay]

Just don't do it in on your driveway; It pumps a lot of nasties out the back end. Should only really be done whilst driving so that the pollution is not concentrated to one spot. Plus you want the van in motion ideally at speed as the exhaust gets very hot during a regen so better to have some airflow to help cool it.

You shouldn’t generally need to force one, the van should take care of itself, unless you are in an extreme environment.

My van went into limp mode at 3700m. Got down to 2800m and tried driving at 2200-2500 rpms for awhile but that didn't work. We were in the mountains in Ecuador and couldn't get any lower.

Only option (other than manual cleaning) was forced Regen while parked, followed by oil change.

At VW in Peru, they do a forced Regen while parked before every oil change.

 

[Peter84]

Don’t have anything to comment on your question but is there a place to follow your journey? Do you maybe have a weblog or something? Overlanding South America in a Cali sounds awesome!

 

[flymartin]

Have you tried it above 3300m?

I found Carista just fools the ECU into thinking the soot is at 30g, but it doesn't solve the attitude issue

That's interesting. I had assumed Carista (and other OBD apps) simply sent a signal "start regen now". If in fact they are fooling the ECU into thinking soot is at 30g, then they must also be spoofing at least a couple of other parameters, like possibly oil temp etc. I too have found that, contrary to the VW advice, regens can start automatically on slow, short, low-revs drives, but never immediately from a cold start on the driveway.

If Carista works by fooling the ECU that all conditions for a regen have been met, perhaps they just don't know about the altitude condition. You could write to them and explain it and they might update the app to spoof altitude as well?

 

[Chris Ratay]

Don’t have anything to comment on your question but is there a place to follow your journey? Do you maybe have a weblog or something? Overlanding South America in a Cali sounds awesome!

Thanks Peter.

Our journeys are at RatayTeam.com

You can opt to follow me and our frequent updates on FB (rather than friend request) - https://www.facebook.com/chris.ratay

We're heading back for our next leg November - April through Patagonia/Antarctica

 

[Chris Ratay]

That's interesting. I had assumed Carista (and other OBD apps) simply sent a signal "start regen now". If in fact they are fooling the ECU into thinking soot is at 30g, then they must also be spoofing at least a couple of other parameters, like possibly oil temp etc. I too have found that, contrary to the VW advice, regens can start automatically on slow, short, low-revs drives, but never immediately from a cold start on the driveway.

If Carista works by fooling the ECU that all conditions for a regen have been met, perhaps they just don't know about the altitude condition. You could write to them and explain it and they might update the app to spoof altitude as well?

Auto Regenerations happen without most of us knowing - no lights or sounds, just a minor bump in rims.

When forcing with Carista or VCDS, the ECU is fooled into thinking there's 30g, then the DPF light comes on. About 30 second later the temp climbs from ~300C to 500C and the burning starts.

As for writing to VW, I have no idea who to talk to. I'm based in Hungary and they sell very few here. In Peru I was dealing with the heads off VW Peru but they communicate everything through Brasil, and since only Euro2 in SA, not much happening.

We love the van and are actually brining it back home next year, where the altitude isn't an issue. I was going to take it to Mongolia staying in 2026, but we travel in 4-6 month intervals and I want it here as well.

 

[Chris Ratay]

Here's a video I made the very first time I started monitoring, after the clog in Ecuador.

I later learned how to input the engine parameters to make the % graph more accurate, but this doesn't impact the DPF data.

The Regen started at 2800m altitude and completed itself above 3600m. At the time, I didn't realize it couldn't start the process above 3300m.

 

[temporarysecretary]

I know it's a really controversial topic but in this use case I would delete the DPF in a heartbeat.

I imagine the majority of vehicles you come across overlanding long distances in those parts of the world are probably not euro 6 diesels?

 

[Chris Ratay]

I know it's a really controversial topic but in this use case I would delete the DPF in a heartbeat.

I imagine the majority of vehicles you come across overlanding long distances in those parts of the world are probably not euro 6 diesels?

We looked into this in January and couldn't find a solution. We were told that starting in 2021 VW "locked" the ECU in Transporters from being able to delete the DPF.

I imagine someone will eventually break through with a map program, but I wouldn't want to be among the first to try, especially so far away