NOx code issues

[myribitsbroke]

Good afternoon,
I have read many posts over and over regarding this issue. I am trying to do everything possible to avoid a dealership visit as I am, of course, out of warranty.

I have a P2BA6 (NOx exceedance) and a P1A58 code (NOx regen required), which lights up the DPF and MIL. I had the DPF replaced under warranty about 30k miles ago. Also had the thermostat, catalytic converter, and cold weather intercooler kit installed about 25k miles ago under warranty, and during both of those warranty visits the EGR valve was cleaned. A few short months after the last warranty service, DPF and MIL came on with aforementioned codes, and of course I am now out of warranty. I brought it to my local VW shop, they performed a forced regen which cleared the DPF light for about 10 miles before it came back on, and they said that the P2BA6 was a "dealer code" that they couldn't figure out?

I also occasionally have the DPF light off, with flashing glow plug light. I also popped a P0299 and a P0638 a couple days ago which have cleared themselves out.

Yesterday, I performed an oil change and swapped out the glow plugs. I also checked the throttle valve, and that looked nice and clean. After all my extensive research, I used my OBDELEVEN to manually start a NOx regeneration (channel 18) and drove for over an hour in each direction. No codes cleared.

But, I am not sure I performed the NOx regen correctly. I changed the value to 0001 and it said function not available. I returned to the screen, and the value had indeed changed to 0001 from 0000, so I assumed that meant the NOx regen was active. The soot level was 0.9, then dropped to 0.6, 0.3, then 0. The NOx load stayed constant at 15.97 the entire drive, and this value has not changed in quite some time. After the first hour and ten minutes, I pulled over to stop and re-start the car. Still had codes. Set value to 0001 again, same thing as before, still codes. However, this time the soot number jumped up to like 19 or 20, then started to drop, quickly at first, then slowly until it got down to 0.3 again.

When opening channel 104 on Live Data, I had at the top 0xFF02 done(or something like that, I should've taken a screen shot.) Value 1 said 0xFF01, value 2 0xff02, and values 3 and 4 both 0000000. None of this changed at any point during my drive. I have no clue what any of those mean.

Then, when I got home I had another code (P2459) which is now gone.

So, I am not sure if I correctly performed the NOx regen, and if I didn't, I guess I don't know how to.

Also, I checked to make sure engine temps were not dropping below 87C which they did not so I think the (new) thermostat is OK.

My goal is to get the car to be able to pass emissions and then get a delete kit from rawtek, which is an expensive job in itself, so if I could get the codes cleared for even a day or two to pass inspection....

So, if anyone has any advice I'd greatly appreciate it. If not I might have to wave goodbye to this car

 

[dbbyleo]

I'm in the same situation as you are.

New NOx, new thermostat... 6,000 miles later... P1A58 is back. It seems like this is can be a chronic issue... even after a new NOx.

I have 3000 miles left on my emissions warranty... and if the prognosis is that I will always be dealing with this... I'll probably just have to sell the car after this last fix. I'd hate to do that. I love the car. If I can hang on to it for another 5 years/100K miles, I'd love to keep it. But all this DPF this and DPF that... makes me think these cars have a finite shelf life regardless of how well you take care of it... and a new DPF and/or NOx would basically "total" the car.

I'd also be willing to do a delete kit if it means I can keep the car and leave all this DPF issues behind me. But will the car pass emissions with a delete kit?

 

[myribitsbroke]

I'm in the same situation as you are.

New NOx, new thermostat... 6,000 miles later... P1A58 is back. It seems like this is can be a chronic issue... even after a new NOx.

I have 3000 miles left on my emissions warranty... and if the prognosis is that I will always be dealing with this... I'll probably just have to sell the car after this last fix. I'd hate to do that. I love the car. If I can hang on to it for another 5 years/100K miles, I'd love to keep it. But all this DPF this and DPF that... makes me think these cars have a finite shelf life regardless of how well you take care of it... and a new DPF and/or NOx would basically "total" the car.

I'd also be willing to do a delete kit if it means I can keep the car and leave all this DPF issues behind me. But will the car pass emissions with a delete kit?

it depends on how strict your state is. do they perform visual inspections/sniffer at the exhaust or just hook up the obd scanner? if it's the latter and you're properly tuned with no codes you'll pass; if they do the former you won't.

i'm very much considering doing a delete, keeping the emissions equipment and swapping it in for testing every other year. my shop says they have a couple customers who do that. the fuel savings probably don't make up for the cost but if you don't have a payment and don't have to keep getting it fixed (the emissions system is THE problem with these cars; they're otherwise pretty sturdy), im sure you could justify it.

unfortunately i am due for my emissions, i wanna get it to pass before doing the delete but i'm out of warranty and i know it's gonna be pricey.

 

[Tuheeden]

While I love Rawtek they are the premium option. Take a look at Flow Direkt - half the price and it's 2 pieces instead of 3.

And YES keep what you remove. On the JSW removing the DPF is a bit of a trick if you don't remove the subframe (it's kind of a belly roll).

It's really a bummer how many TDI's after the 'fix' have just been one issue after the next. I am sure VW can't wait for these to age out!

 

[dbbyleo]

I guess DPF Delete is not an option in "emissions states" like CO. I called my local diesel shop where I get my emissions test every 2 years, and he confirms it. It will not pass.

Update: My car is still at Audi. Latest from Audi is:
They have failed to resolve the P1A58 code with 2 regen attempts. Audi HQ advised them to do it a 3rd time, which also failed. I'm told the issue has been "escalated at Audi HQ" as to what the tech should do at this point.

[Recall that they had just replaced the NOx converter 6000 miles ago].

After doing a bunch more research on my own, I have to admit my driving habits likely contributed to this. I've always "babied" my cars - not driving them hard, always looking to extend fuel economy etc; I always let my cars warm up... and because "it seemed like these TDIs took longer to warm up compared to my gas cars" I actually would let it sit idle warming up anywhere from 10-15 min every morning.

I'ce read since then that both of these habits contribute to soot build-up.

A local diesel shop confirms this. He said it doesn't matter which make, Chevy, Ford, Dodge, VW/Audi... all diesel with emissions controls like these are susceptible to this issue. "They see it all the time" especially with people who buy big diesel trucks "for show only" and never put any real load on it, like towing.

 

[myribitsbroke]

I guess DPF Delete is not an option in "emissions states" like CO. I called my local diesel shop where I get my emissions test every 2 years, and he confirms it. It will not pass.

Update: My car is still at Audi. Latest from Audi is:
They have failed to resolve the P1A58 code with 2 regen attempts. Audi HQ advised them to do it a 3rd time, which also failed. I'm told the issue has been "escalated at Audi HQ" as to what the tech should do at this point.

[Recall that they had just replaced the NOx converter 6000 miles ago].

After doing a bunch more research on my own, I have to admit my driving habits likely contributed to this. I've always "babied" my cars - not driving them hard, always looking to extend fuel economy etc; I always let my cars warm up... and because "it seemed like these TDIs took longer to warm up compared to my gas cars" I actually would let it sit idle warming up anywhere from 10-15 min every morning.

I'ce read since then that both of these habits contribute to soot build-up.

A local diesel shop confirms this. He said it doesn't matter which make, Chevy, Ford, Dodge, VW/Audi... all diesel with emissions controls like these are susceptible to this issue. "They see it all the time" especially with people who buy big diesel trucks "for show only" and never put any real load on it, like towing.

i dont doubt that your driving habits contributed to it...the first time. but 6000 miles after replacement is not enough for you to be having these problems even if you doubled how bad your habits were. i had about 20k on a replaced dpf, thermostat, nox converter, intake manifold, intercooler icing kit, 2 egr cleanings, and still popped the nox codes. during that time (winter-spring) i was plugging the car in at night (has an engine block heater) when it was cold and i was driving pretty sporty and on the highway every day but it didn't matter.

 

[myribitsbroke]

I guess DPF Delete is not an option in "emissions states" like CO. I called my local diesel shop where I get my emissions test every 2 years, and he confirms it. It will not pass.

Update: My car is still at Audi. Latest from Audi is:
They have failed to resolve the P1A58 code with 2 regen attempts. Audi HQ advised them to do it a 3rd time, which also failed. I'm told the issue has been "escalated at Audi HQ" as to what the tech should do at this point.

[Recall that they had just replaced the NOx converter 6000 miles ago].

After doing a bunch more research on my own, I have to admit my driving habits likely contributed to this. I've always "babied" my cars - not driving them hard, always looking to extend fuel economy etc; I always let my cars warm up... and because "it seemed like these TDIs took longer to warm up compared to my gas cars" I actually would let it sit idle warming up anywhere from 10-15 min every morning.

I'ce read since then that both of these habits contribute to soot build-up.

A local diesel shop confirms this. He said it doesn't matter which make, Chevy, Ford, Dodge, VW/Audi... all diesel with emissions controls like these are susceptible to this issue. "They see it all the time" especially with people who buy big diesel trucks "for show only" and never put any real load on it, like towing.

question about your source at the diesel shop: did he say why it won't pass? it won't pass visual inspection? or is there something in the ecm that would prevent it from passing if deletes are performed

 

[dbbyleo]

I didnt ask specifics... but if diesel emissions in CO are like anything like gas emissions test... its more than "visual." At the gas emission testing stations (where I can see the process)... the car is hooked up to all sorts of probes, including in the tailpipe, obd, etc. But at the diesel shop... I cant see what they actually do, other than I've read the car is put on a dyno and driven up to 60pmh etc.

So if its not my driving habits... what gives? And if yours, after all that work on the entire emissions system... still popped the NOx code after only 20L miles... ***?? Do you still have your car? I mean... it doesnt seem like a car you'd want to hang on to (after the emissions warranty is up) if this crap keeps happening. How can you afford to?? Especially if you live in an emissions state. Did you do all that work yourself, or was that done under warranty.

 

[myribitsbroke]

i do have the car still and yes all that work was done under warranty (which I am now out of). it actually runs pretty well, although fuel mileage is down 10-15% from when I first bought it. my emissions aren't due until this coming april so I'm trying to formulate a plan to get out of this. I like the car, I've put some work into it for towing (hitch, wired to pull a trailer, upgraded rear springs to add 2" in height). It's fun and comfortable to drive. But obviously these emissions issues are forcing me to have to figure this out or get rid of it by next spring.

 

[dbbyleo]

Are you saying then that you have the P1A58 NOx code on right now?

 

[myribitsbroke]

Are you saying then that you have the P1A58 NOx code on right now?

yes, i've had that code along with P2BA6 since last summer.

 

[dbbyleo]

Ugh.
See thats what I'm afraid of. I've 3000 miles left on the warranty. And this time around those guys probably put on 200miles just trying to regen it.
I'm really considering selling it as soon as I get it gets fixed this time around.

Keep me posted on what you end up doing.

 

[myribitsbroke]

Ugh.
See thats what I'm afraid of. I've 3000 miles left on the warranty. And this time around those guys probably put on 200miles just trying to regen it.
I'm really considering selling it as soon as I get it gets fixed this time around.

Keep me posted on what you end up doing.

If you're under warranty your best bet is to let the dealer eat that cost and then get rid of it before another issue pops up. it's a shame what the government did to these cars

 

[dbbyleo]

Update: Just got my car back from Audi. After several (5 times) failed attempts to regen and fix the P1A58 code. On the fifth try, the check engine light came on - P13D4 and P13D6. They couldn't tell how this was related to the P1A58 (NOx regen required), but replaced Cylinder 3 glow plug and pressure sensor. With the MIL off, they took it for a 6th attempt to regen. Finally, after putting on over 500 miles on my car, the DPF warning light went off.

I got the car back home. I wanted to check for myself so I hooked it up the VCDS. And sure enough... there are no malfunctions in 01 - Engine.

I checked the DPF stats...

Oil Ash Volume (241.1): 168ml (car has 148K miles) ... from what I this is really all just calculated on the mileage of the car.

Soot Load Calculated (241.2): 7.2g ... from what I understand, this is a good indicator of when I should take the car for a "burn drive" (ie drive in sport mode intentionally) for passive regen... i think I read at 20g the car will do an active regen (but not positive).

Particulate Filter Differential Pressure: 8mbar (@idle), 18mbar (@2000 rpm - stationary) ... from what I understand, this is really the indicator of how clogged your DPF is. Anything above 27mbar would indicated a very clogged DPF and by then, there may be all sorts of DPF/MIL light on and fault codes.

My problem is ... all these stats is this is related to the DPF, not the NOx cat/storage/converter. Does anyone know what/where in VCDS to get measurements of the conditions of the NOx?

 

[myribitsbroke]

Update: Just got my car back from Audi. After several (5 times) failed attempts to regen and fix the P1A58 code. On the fifth try, the check engine light came on - P13D4 and P13D6. They couldn't tell how this was related to the P1A58 (NOx regen required), but replaced Cylinder 3 glow plug and pressure sensor. With the MIL off, they took it for a 6th attempt to regen. Finally, after putting on over 500 miles on my car, the DPF warning light went off.

I got the car back home. I wanted to check for myself so I hooked it up the VCDS. And sure enough... there are no malfunctions in 01 - Engine.

I checked the DPF stats...

Oil Ash Volume (241.1): 168ml (car has 148K miles) ... from what I this is really all just calculated on the mileage of the car.

Soot Load Calculated (241.2): 7.2g ... from what I understand, this is a good indicator of when I should take the car for a "burn drive" (ie drive in sport mode intentionally) for passive regen... i think I read at 20g the car will do an active regen (but not positive).

Particulate Filter Differential Pressure: 8mbar (@idle), 18mbar (@2000 rpm - stationary) ... from what I understand, this is really the indicator of how clogged your DPF is. Anything above 27mbar would indicated a very clogged DPF and by then, there may be all sorts of DPF/MIL light on and fault codes.

My problem is ... all these stats is this is related to the DPF, not the NOx cat/storage/converter. Does anyone know what/where in VCDS to get measurements of the conditions of the NOx?

Using my OBDEleven I go to Long Adaptation and go to channel 18. You have to put in security access 12233 if I remember correctly. This tells me the temperature of the NOx converter, soot load, and nox load. I can also manually start a NOx regeneration. For me the soot load will drop as I drive during regen, eventually to 0, but the NOx load stays at 15.97.

 

[dbbyleo]

Ok. Thanks for the reminder. I forgot in the Long Adaptation for NOx Regen (Ch 18), it shows the NOx load. I've only driven that car from the Audi (about 13miles) since I they got the P1A58 code to clear. And as of right now NOx Load is at 4.56g.

Am I correct to assume this is the value I need to keep an eye on... and an indicator for me to know when I should drive the car in sport mode intentionally for a good passive regen to manage this number?

 

[myribitsbroke]

Ok. Thanks for the reminder. I forgot in the Long Adaptation for NOx Regen (Ch 18), it shows the NOx load. I've only driven that car from the Audi (about 13miles) since I they got the P1A58 code to clear. And as of right now NOx Load is at 4.56g.

Am I correct to assume this is the value I need to keep an eye on... and an indicator for me to know when I should drive the car in sport mode intentionally for a good passive regen to manage this number?

I can't say I know anything for sure. The information on this particular issue seems very limited. I just saw another thread where someone was having issues like this and they replaced the ECM, after replacing the NOx converter and sensors. So who knows?