Passat Active Regens - How Often [Fans run after shutdown]

Lightflyer1 · Feb 4, 2015

The lamp comes on only when there is an issue or problem. You "don't" want to see the light come on. Regens and DEF have nothing to do with each other. Completely separate functions and uses. The only real way to know is to have gauges that show temps of EGT and DPF in/out. Torque app for android or Scangauge II setup.

tdiatlast · Feb 4, 2015

2 gallons DEF in 10k miles? Regen light coming on?
Sounds do me like you've got a problem that needs VW service attention.

czeetah · Feb 8, 2015

I thought there was no such thing as a regen light ..

meerschm · Feb 8, 2015

An interrupted regen may result in one being initialized on next cycle, but this depends on how long the regen which was interrupted had been going on. if it was just started, there will still be a need. if it was half way or more (for example) it may wait.

there is an engine controller measurement parameter, "requested regens" which I have watched on my '09 jsw which increments from 1 to 5, then decrements (counts down) during a regeneration.

Group 105-1 in my engine controller is Requested Regenerations.

Group 240-2, Mileage since regen km, is reset at the end of the regeneration period.

I pulled some graphs from my drive and sooner or later will put together a little info DIY

photos with graphs are at:

http://www.myturbodiesel.com/gallery/albums/regeneration-data.317/

jrm · Feb 8, 2015

I believe only Ford F series trucks have the Active regeneration in process light, and also the "postpone" regeneration button if one plans on shutting down soon.
Great feature that all Clean diesels should have

Lightflyer1 · Feb 8, 2015

czeetah said:
I thought there was no such thing as a regen light ..

There is a light, but it tells you something is wrong, not when everything is going smoothly.

SoTxBill · Feb 8, 2015

Biz said:
Does the regen cycle create an odor? I smell a slight kind of thickly sweet engine odor at times. Seems worse now (16K miles) than when the car was new. I usually drive 40 miles at a time for my normal commute. Doesn't seem normal. My throat was burning on a long drive recently (all-day). Is it something I should have the dealer look at, or will it go away?

Same problem. .Dealer said it was the cedar pollen and it would go away in a couple of weeks.

goodysgotacuda · Feb 8, 2015

jrm said:
I believe only Ford F series trucks have the Active regeneration in process light, and also the "postpone" regeneration button if one plans on shutting down soon.
Great feature that all Clean diesels should have

Indeed, class 8s have it as well. I believe it is mostly for off highway conditions where one could end up in tall grass. That could get interesting during a regen.

VeeDubTDI · Feb 9, 2015

Parking in tall grass, fuel islands where you don't want to melt the canopy, or any time when people could be working around the hot exhaust components.

oceanrunner · Mar 13, 2015

2015 Jetta TDI 6M with 4700 miles.
Frequently, while driving during the day I get a lot of high RPM's in the 900+ and was wondering if that was regens and how often they should be occurring? Also noticed some soot on the rear of the car like the kind you get when it rains while driving....is this normal?. I did a little playing around with my VCDS. It doesn't appear that I am using that much UREA or maybe this is normal.

Address 01: Engine (04L 906 016 AJ)

18:35:15
629 Particle filter; kilometers since last regeneration 66304 m
630 Particle filter; oil ash volume 0.00 l
631 Particle filter; oil ash volume 1.4 g
632 Particle filter; soot mass calculated 8.07 g
633 Particle filter; soot mass measured 0.33 g
634 Particle filter; time since last regeneration 7649 s
635 Particle filter; unburned fuel calculated 0.000
636 Particulate filter ash load limit 80.00 g
637 PDTC drive cycle conditions status-Bit 0 37
674 Reducing agent fill level 92.57 %
676 Reducing agent inj. quantity; spec. value 0.0 mg/s
707 Remaining vehicle distance until reducing agent deficiency 12460.20 km

pedorro · Mar 13, 2015

oceanrunner said:
2015 Jetta TDI 6M with 4700 miles.
Frequently, while driving during the day I get a lot of high RPM's in the 900+ and was wondering if that was regens and how often they should be occurring? Also noticed some soot on the rear of the car like the kind you get when it rains while driving....is this normal?. I did a little playing around with my VCDS. It doesn't appear that I am using that much UREA or maybe this is normal.

Address 01: Engine (04L 906 016 AJ)

18:35:15
629 Particle filter; kilometers since last regeneration 66304 m
630 Particle filter; oil ash volume 0.00 l
631 Particle filter; oil ash volume 1.4 g
632 Particle filter; soot mass calculated 8.07 g
633 Particle filter; soot mass measured 0.33 g
634 Particle filter; time since last regeneration 7649 s
635 Particle filter; unburned fuel calculated 0.000
636 Particulate filter ash load limit 80.00 g
637 PDTC drive cycle conditions status-Bit 0 37
674 Reducing agent fill level 92.57 %
676 Reducing agent inj. quantity; spec. value 0.0 mg/s
707 Remaining vehicle distance until reducing agent deficiency 12460.20 km

Best way to monitor regens is to use a device to monitor exhaust gas temperatures. The Scanguage II, Auto-Polar FIS+, and various phone apps using a Bluetooth OBD-II adapter will do the job. The FIS+ unit will also display the miles since last regen, DPF soot load, and DPF regen status.

I've found my regen periods are pretty consistent so long as my driving patterns are consistent. City driving and shorter trips will result in more frequent regens than highway driving.

jhinsc · May 13, 2015

I've been tracking how often DPF regen's occur in my Passat. I only note it when at a stop, I notice the fast idle and fan running. I may miss one here and there if it happens while I'm cruising, but after tracking it for over a month, it seems to be happening every 150 - 200 miles. Does that seem excessive or normal? I have about 17,700 miles, and my normal commute is 23 miles each way, with 3 stop signs and 16 or 17 traffic lights each way. Some days it seems I hit every red light and others day only a few. Mileage is great, averaging over 42 mpg.

VeeDubTDI · May 13, 2015

150-200 miles of city stop and go sounds about right to me. Once you're on the highway, it will increase to 300 miles or so.

Busydiver · May 13, 2015

I have a similar distance commute but with less stop lights etc. I also see regens in the same range maybe a bit higher around 225 or so. I would say you are in a normal range. Anyone driving the TDI on extended highway mileage will likely see regens in the upper 300 to 400+. The benefit of the highway cruise is the higher DPF temps are acting like a regen cycle to burn off some of the soot. Eventually it will go into an automatic regen as part of the programming even with significant highway mileage.

jhinsc said:
I've been tracking how often DPF regen's occur in my Passat. I only note it when at a stop, I notice the fast idle and fan running. I may miss one here and there if it happens while I'm cruising, but after tracking it for over a month, it seems to be happening every 150 - 200 miles. Does that seem excessive or normal? I have about 17,700 miles, and my normal commute is 23 miles each way, with 3 stop signs and 16 or 17 traffic lights each way. Some days it seems I hit every red light and others day only a few. Mileage is great, averaging over 42 mpg.

jhinsc · May 14, 2015

Thanks - I won't worry about it then. The only annoyance I have is if it decides to do a regen just before I arrive at work. Sometimes if short on time, I'll turn off the engine, and restart it immediately to stop the regen and let the engine cool down - it only take a minute or two for the fan to shut off.

Dfc41889 · May 14, 2015

tdiatlast said:
suprnice said:

I had an interrupted regen once after I parked and turned off the engine, fan under the hood running like crazy with loud noise, after a few minutes, didn't know what happened, I restarted the engine and the loud sound was gone, hopefully it didn't do much damage..[/QUOTE]

"Interrupting a regen" does NO damage of any kind. When the car is moving, during a regen, the flow of air through the radiator is usually sufficient to cool the engine. If the vehicle stops moving, the heat rises, triggering the high-speed fans.

As soon as the engine is turned off, any regen in progress is stopped. However, the residual heat might require the fans to continue to run. Therefore, if the fans are still running after the engine is turned off, it is ONLY to dissipate residual heat...the regen has stopped.

An interrupted regen will re-start, once the engine is re-started, and comes up to a temp hot enough to trigger the regen.

Click to expand...

Not to discount this, but in the turbo failure thread, it is a common belief that the main reason for the turbo failures in the 2012-2014 Passat TDI's is the interruption of the regen due to lack of continued oil flow to the turbo after the engine shuts off. It makes sense that during a regen the turbo is super hot and when you shut the engine down, oil flow stops, and the turbo is somehow weakened or damaged by the excessive heat. Thoughts?

pparks1 · May 14, 2015

I have quite often left the car running in the parking lot, walk my stuff in to my desk and then head back out to the car. I've interrupted a few, but I usually try to pay attention and letthem run their course.

smoav8r · May 15, 2015

This thread is a perfect example of the value of an OBDII bluetooth adapter and the Torque app for your Android phone.

tdiatlast · May 15, 2015

...or a ScanGaugeII...
...or, listening to your car before you shut it off...

lithgow · May 21, 2015

So while idling, you can tell by the increased rpm to 1000 or so that it is in an active regen? Is there a way to tell while driving (other than obd scan like torque)? How long does regen last and how often does a typical car go through it? I understand that it varies by soot load.... but just in general is it every 5000 miles or so? Just wanting to learn as much about my car as I can. Thanks

Bobmws · May 21, 2015

Recently retired (yay!), I've gone from an 80 mile RT commute to short trips in the 4 to 20 mile range. I've noticed regens occurring more frequently at the end of a short trip then when I was commuting. I've learned to look at the idle speed and listen for the fans before shutting down. Car is coming up to 50k miles.

Lightflyer1 · May 22, 2015

lithgow said:
So while idling, you can tell by the increased rpm to 1000 or so that it is in an active regen? Is there a way to tell while driving (other than obd scan like torque)? How long does regen last and how often does a typical car go through it? I understand that it varies by soot load.... but just in general is it every 5000 miles or so? Just wanting to learn as much about my car as I can. Thanks

According to Torque on my car rpms at idle are 830 rpms. When in a regen they are 930 rpms. While driving without gauges it will be very difficult to tell. My regens last about ten minutes when running down the highway nonstop. Regens happen every 200 to 400 miles depending on the driving conditions.

jrnudd89 · May 25, 2015

Dfc41889 said:
tdiatlast said:

Not to discount this, but in the turbo failure thread, it is a common belief that the main reason for the turbo failures in the 2012-2014 Passat TDI's is the interruption of the regen due to lack of continued oil flow to the turbo after the engine shuts off. It makes sense that during a regen the turbo is super hot and when you shut the engine down, oil flow stops, and the turbo is somehow weakened or damaged by the excessive heat. Thoughts?

Click to expand...

I'd definitely agree with this. In general, keeping the lubricant cool when the flow stops will directionally improve component life. Oil coking in the bearing housing can be an issue if hot oil sits at shutdown. I try not to interrupt regents for this reason upon shutdown, but sometimes it cannot be avoided.

jrnudd89 · May 25, 2015

lithgow said:
So while idling, you can tell by the increased rpm to 1000 or so that it is in an active regen? Is there a way to tell while driving (other than obd scan like torque)? How long does regen last and how often does a typical car go through it? I understand that it varies by soot load.... but just in general is it every 5000 miles or so? Just wanting to learn as much about my car as I can. Thanks

If you pay attention frequently, you may be able to spot an active regent by noticing a slight dip in highway instantaneous fuel economy, assuming you know what it normally runs. No substitute for monitoring exhaust gas temps however.

Passat Active Regens - How Often [Fans run after shutdown]

Top Post Dawg

Top Post Dawg

Veteran Member

Top Post Dawg

Veteran Member

Top Post Dawg

Top Post Dawg

Veteran Member

Wanderluster, Traveler, TDIClub Enthusiast

Veteran Member

Veteran Member

Veteran Member

Wanderluster, Traveler, TDIClub Enthusiast

Veteran Member

Veteran Member

New member

Veteran Member

Veteran Member

Top Post Dawg

Member

Veteran Member

Top Post Dawg

Member

Member