P2459/08863 DPF Regeneration Frequency

[frizbo]

Update: had a new DPF installed under warranty!

 

[740GLE]

how many miles were on the orginal?

 

[tristan81491]

Nice! Having the same issue, had sensors replaced by dieselgate but still same code. How long did it take for them to get the parts and do the work?

 

[frizbo]

Nice! Having the same issue, had sensors replaced by dieselgate but still same code. How long did it take for them to get the parts and do the work?

Sorry I missed this,
It was about a 2 week turnaround. i'm in southern ontario, canada.

 

[IanEricson]

A chunk of carbon. I blow those tubes out every time I install a new DPF, and the top side one often has some black stuff in it. Minimal, but it is there.

Question for oilhammer: Where do you buy DPFs and how much do they cost? I cannot find any for sale.

 

[oilhammer]

Local dealer.

 

[bradleyj]

A couple of weeks ago the CEL in my 2015 Sportwagen came on and a P2459 code was set. I cleared the code to turn the light off and made an appointment with my dealer for today to have it checked out. They told me they won't look at this under warranty unless the CEL is on and the code is active in the system. I've put several hundred miles on the car since I cleared the code but the CEL hasn't come back on yet. Is there a clever way I might be able to force this code to set again? Maybe disconnect one of the hoses to the DPF pressure sensor? I'd sure like to get this taken care of before my emissions warranty runs out in 8,000 more miles.

 

[TurboABA]

Did you save your code FF prior to nuking it?

 

[bradleyj]

No, I just used a cheap scan tool to view and clear the code.

 

[TurboABA]

That's unfortunate especially since clearing the DTC will also reset the readiness monitors, so now you'll have to satisfy quite a few driving conditions before it will get a chance to throw the code again IF something was legit as far as being faulty.... start short tripping it a lot to "aid" it.

 

[bradleyj]

Yeah, ok. Thanks.

 

[TurboABA]

It's been a while since I've looked at anything with the 2L CR, but if I recall correctly from when I drove one, the active regen takes place at a soot load between 19-30g so if you have any means of monitoring the loading and interrupt the attempted regens enough to load it up to 30g, it should throw a MIL.

 

[bradleyj]

Can you monitor this and manually stop regens through VCDS?

Actually, this would probably set a different code though, wouldn't it? I would want the P2459 to be set so they'll diagnose and address that problem (regens too frequent) specifically. I'm not sure that the solution would be the same for whatever other code stopping regens would set.

 

[Lightflyer1]

My Beetle kicks off at around 24 +/-. Every 200 miles or so. Depends some on your driving habits. Monitored with VAGDPF.

 

[TurboABA]

My Beetle kicks off at around 24 +/-.

Sounds plausible as that's right about in the middle of the range I seem to recall....

 

[TurboABA]

Can you monitor this and manually stop regens through VCDS?

Actually, this would probably set a different code though, wouldn't it? I would want the P2459 to be set so they'll diagnose and address that problem (regens too frequent) specifically. I'm not sure that the solution would be the same for whatever other code stopping regens would set.

No such option that I'm aware of....

 

[LenP]

Does the DPF Pressure sensor needs to be re-learned?

 

[LukesCRUA]

On mine there is no option for adapting the dpf pressure sensor

 

[tristan81491]

No adaptation needed

 

[MidwestLoon]

My car is throwing P2459, but isn't confirmed yet in VCDS
My car is also throwing P2478 - Exhaust Temp Out Of Tolerance for EGT Sensor 1 Bank 1
I haven't been able to diagnose this properly yet since it throws both these codes at the same time

I part cannoned the pre-turbo EGT sensor (mounted on the exhaust manifold), but that didn't fix these codes. My logs for Bank 1 Sensor 1 readings seem normal, so I don't understand why my car is deciding to throw this code.

I figured it might be time to start looking at these pressure sensors. I'll try blowing the lines and seeing if there is a change.
I'll report back afterwards. I'm just curious if anyone else here has some insight or additional thoughts

 

[x1800MODMY360x]

My car is throwing P2459, but isn't confirmed yet in VCDS
My car is also throwing P2478 - Exhaust Temp Out Of Tolerance for EGT Sensor 1 Bank 1
I haven't been able to diagnose this properly yet since it throws both these codes at the same time

I part cannoned the pre-turbo EGT sensor (mounted on the exhaust manifold), but that didn't fix these codes. My logs for Bank 1 Sensor 1 readings seem normal, so I don't understand why my car is deciding to throw this code.

I figured it might be time to start looking at these pressure sensors. I'll try blowing the lines and seeing if there is a change.
I'll report back afterwards. I'm just curious if anyone else here has some insight or additional thoughts

DTC, Error Message, Malfunction Criteria and Threshold Value
P2459,
Diesel Particulate Filter Regeneration Frequency,
PM trap loading > dynamicly rising threshold [f(simulated engine emissions)]

P2478,
Exhaust Gas Temperature Out of Range Bank 1 Sensor 1,
Control deviation > limit from MAP f(engine speed, torque)

VCDS would have freeze frame data for those error codes to help diagnose more.

 

[TurboABA]

My car is throwing P2459, but isn't confirmed yet in VCDS
My car is also throwing P2478 - Exhaust Temp Out Of Tolerance for EGT Sensor 1 Bank 1
I haven't been able to diagnose this properly yet since it throws both these codes at the same time

I part cannoned the pre-turbo EGT sensor (mounted on the exhaust manifold), but that didn't fix these codes. My logs for Bank 1 Sensor 1 readings seem normal, so I don't understand why my car is deciding to throw this code.

I figured it might be time to start looking at these pressure sensors. I'll try blowing the lines and seeing if there is a change.
I'll report back afterwards. I'm just curious if anyone else here has some insight or additional thoughts

You're not showing us anything, and we can't see what you're seeing.
Post scan\logs\whatever.

 

[GBaugh]

If everything else checks out ok, sensing hoses are clear and you're confident the dpf diff psi sensor is ok, keep in mind that the dpf accumulates not just soot but ash also. Ash is not burnt off with regens. It continuously accumulates. If you look in the owners manual there is even a service interval for ash cleaning although I don't think dealerships are even equipped for cleaning ash. There may be just enough exhaust restriction to elevate the dpf diff psi sensor values and cause frequent regens, but with no significant loss of pwr yet. If there is an exh restriction, it might show up on the scan tool with a reduction in MAF value since engine won't be breathing optimally but you would want to look at the MAF value when egr is closed, under large load.

As already mentioned, there are separate adaptations for dpf diff psi and exhaust psi sensors which would definitely be a good idea with new sensors but I would NOT reset the dpf unless it is actually replaced. Resetting the dpf without replacing it can throw off the soot models.

 

[MidwestLoon]

You're not showing us anything, and we can't see what you're seeing.
Post scan\logs\whatever.

You’re right, I’m sorry. I was just throwing in my thoughts on my preliminary work towards this from my desktop. I wasn't expecting to receive so many helpful comments right away:

Here's the freeze frame from my laptop:

I'll be honest, I overlooked the P0470 until I saw this just now.

8852 - EGT Sensor 1 Bank 1
          P2478 00 [11101100] - Exhaust Gas Temperature Out of Tolerance
          MIL ON - Intermittent - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 3
                    Mileage: 178964 km
                    Date: 2025.05.26.
                    Time: 14:18:16

                    Engine speed: 2060.00 /min
                    Normed load value: 54.1 %
                    Vehicle speed: 109 km/h
                    Coolant temperature: 101  C
                    Intake air temperature: 39  C
                    Ambient air pressure: 980 mbar
                    Voltage terminal 30: 13.680 V
                    Unlearning counter according OBD: 40
                    Exhaust gas temperature sensor 1: 793.3  C
                    Exhaust gas temperature sensor 2: 606.3  C
                    Exhaust gas temperature sensor 3: 631.4  C
                    Exhaust gas temperature sensor 4: 590.0  C
                    Temp sensor for low-pressure EGR after cooler: raw value: 124.5  C
                    Shut-off timer: last engine shut-off time: 185 s

9655 - Control Circuit for Reductant Tank Heating
          P202A 00 [01100000] - Open Circuit
          Intermittent - Not Confirmed - Tested Since Memory Clear

9764 - Exhaust Pressure Sensor 1
          P0470 00 [00100100] - Malfunction
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 178987 km
                    Date: 2000.00.00
                    Time: 00:00:00

                    Engine speed: 0.00 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 18  C
                    Intake air temperature: 17  C
                    Ambient air pressure: 970 mbar
                    Voltage terminal 30: 10.860 V
                    Unlearning counter according OBD: 40
                    Air mass: actual value (mg/stroke): 0.0 mg/stroke
                    Specified value of low pressure EGR valve: 100.00 %
                    Actual value of low pressure EGR valve: 100.01 %
                    Low-pressure EGR valve: offset closed: -0.22 %
                    Low-pressure EGR valve: status-Bits 0-7: 0
                    Low-pressure EGR valve: status-Bits 0-7: 0
                    Low-pressure EGR valve: status-Bits 0-7: 0
                    Low-pressure EGR valve: status-Bits 0-7: 55
                    Low-pressure EGR valve: uncond voltage: 1006.6 mV

8863 - Particulate Filter
          P2459 00 [01100101] - Regeneration Frequency
          Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 178958 km
                    Date: 2025.05.26.
                    Time: 14:15:11

                    Engine speed: 1869.50 /min
                    Normed load value: 69.0 %
                    Vehicle speed: 98 km/h
                    Coolant temperature: 100  C
                    Intake air temperature: 42  C
                    Ambient air pressure: 990 mbar
                    Voltage terminal 30: 13.740 V
                    Unlearning counter according OBD: 40
                    Exhaust gas jet volume in particle filter: 259.4 m /h
                    Particle filter: difference pressure: 245 hPa
                    Particle filter: soot mass measured: 22.76 g
                    Particle filter: soot mass calculated: 22.75 g
                    Particle filter: differential pressure: dynamic offset: -6 hPa
                    Exhaust gas temperature sensor 3: 392.7  C
                    Exhaust gas temperature sensor 4: 364.6  C

Readiness: 1 1 0 0 0

 

[TurboABA]

Not showing full scan, thus I have no idea what your current mileage iis, or when that FF data is from. Maybe the 3 fault occurences are from the last 2 weeks or maybe they happened the same day...
Replace your EGT#1 for starters

 

[MidwestLoon]

Not showing full scan, thus I have no idea what your current mileage iis, or when that FF data is from. Maybe the 3 fault occurences are from the last 2 weeks or maybe they happened the same day...
Replace your EGT#1 for starters

It’s all I have at the moment. It’s ~108K miles. This was pre EGT sensor replacement. I did send it on the EGT sensor. The same 2 codes were still being thrown. Anyway, I have people smarter than me taking a look. I’ll update if I have something relevant to share

 

[LukesCRUA]

There’s a few of us here with the p2459 problem lol

 

[technobabble]

The pressure sensor may be restricted or giving a false value. The sensor for the DPF is the one on the bracket over by the coolant bottle. The one for the EGR is the one back atop the valve cover. They both are functionally the same thing, and both tee into the same post-DPF port for their reference, but since you do not have any EGR flow DTCs I would suspect that part is clear.... at least to the tee.

So take the sensor off, remove the two hoses (they are clamped on, you'll need a T30 bit to get it all apart). Note the position of the hoses, they cannot be swapped or the sensor won't work right.

Once the hoses are off, look inside them for any debris or water condensation. Look inside the sensor's nipples, too. You can blow air through the hoses to make sure they are clear, you won't hurt anything.

If that all checks out, I'd be inclined to just try a new sensor, do all the Adaptations for everything, and see if that doesn't get your regen frequency back down.

Do you have any pics that show where this is located? I am unable to find mine.

TIA

 

[Tom in PT]

Its 7 inches "southeast" of the coolant bottle right next to the engine cover, couple of hoses coming off it and an electrical plug. You are looking right at it when you open the hood, stand in front of the car, and look to the left of the engine cover. Its on its side, 1/2 the size of a credit card . . . . . .