Jeep Garage  - Jeep Forum banner

exhaust system regeneration process

143K views 191 replies 63 participants last post by  Demicortez 
#1 ·
My 2014 diesel gc has gone thru the exhaust system regeneration process at least twice and i have less than 1500 miles on the car. Is that a normal interval?

Both times i have been able to continue driving like the Evic message says to do but what happens if someday i am in a position where i have to park and shut off the engine while the regeneration process is going on. Is it bad for the car?

Thanks.
 
#2 · (Edited)
Regens will vary depending on driving style. If you idle more than average, or do mainly city driving, your vehicle will go through more regens. The "magic" with highway driving and/or towing, is EGTs (exhaust gas temps) are generally higher and can "oxidize" the particulate matter which has been "caught" in the DPF (diesel particulate filter).

IF you get an EVIC message saying your DPF is xx% full, and a regen is necessary, I would drive until the regen is complete.


** As a sidebar, after reviewing the diesel supplement, if the EVIC says Exhaust Filter XX% Full Safely Drive at Highway Speeds to Remedy. I would plan on driving at highway speeds long enough for the regen to be complete.

(**Our GC diesel supplement reads very close to the Ram Cummins supplement. Evidently our vehicles can go through active regen without an EVIC message, and the EVIC only alerts us if the DPF is too full. IF you turn the vehicle off in this situation, it's no problem. This situation occurred on our GC once so far in 2200 miles, and it just smelled funny in the garage.)

So, in summation, if your EVIC says to drive at highway speeds in order for the DPF to regen, I would do that, and I would not cut off the vehicle until the EVIC says you're good to go.


Below is a link to the GC diesel supplement. Click around to get to the 2014 diesel supplement and open up and check it out!


Jeep Owners | Download an Owners Manual 2004 - 2011 | Jeep
 
  • Like
Reactions: momberose
#5 ·
Regens will vary depending on driving style. If you idle more than average, or do mainly city driving, your vehicle will go through more regens. The "magic" with highway driving and/or towing, is EGTs (exhaust gas temps) are generally higher and can "oxidize" the particulate matter which has been "caught" in the DPF (diesel particulate filter).

IF you get an EVIC message saying your DPF is xx% full, and a regen is necessary, I would drive until the regen is complete.


** As a sidebar, after reviewing the diesel supplement, if the EVIC says Exhaust Filter XX% Full Safely Drive at Highway Speeds to Remedy. I would plan on driving at highway speeds long enough for the regen to be complete.

(**Our GC diesel supplement reads very close to the Ram Cummins supplement. Evidently our vehicles can go through active regen without an EVIC message, and the EVIC only alerts us if the DPF is too full. IF you turn the vehicle off in this situation, it's no problem. This situation occurred on our GC once so far in 2200 miles, and it just smelled funny in the garage.)

So, in summation, if your EVIC says to drive at highway speeds in order for the DPF to regen, I would do that, and I would not cut off the vehicle until the EVIC says you're good to go.


Below is a link to the GC diesel supplement. Click around to get to the 2014 diesel supplement and open up and check it out!


Jeep Owners | Download an Owners Manual 2004 - 2011 | Jeep

I'm relatively new to the diesel world - but if I am about to pull into my parking garage downtown at work, and evic tells me I need regen, I should go drive on the freeway and not shut off the jeep? That seems completely asinine and impractical. :confused:
 
#3 ·
We have a stupid situation in Australia, firstly, we have never had a Diesel supplement book, even after 3 years of having the CRD.

But worse, is that our EVIC warning for a full or near full DPF, does NOT come on until it is too late.

So this message - Exhaust Filter XX% Full Safely Drive at Highway
Speeds To Remedy
- comes on, and at the same time our cars are put into limp mode, locking it to 4th gear and restricting revs.

Car after car is having to be towed back to dealers because of this stupid programming fault.
Owners are given no guide that this may even happen, or why it happens in our paperwork.
 
  • Like
Reactions: growler
#7 ·
OPERATION

The oxidation catalysts raise the exhaust gas temperatures to regenerate the DPF , which is passive regeneration. If the passive regeneration cannot keep up with the build up of soot in the DPF, the Powertrain Control Module (PCM) will actively regenerate the DPF to burn off the soot. Residue remains inside the DPF in the form of non burnable ash. Ash comes from the oils and other materials that are trapped in the oils and are present in the soot. Ash is not eliminated by the regeneration cycle. Excessive ash accumulation requires the replacement of the DPF. The DPF uses a silicon carbide wall-flow monolith with a platinum coating to trap particulates. The monolith contains a large number of square parallel channels, which run in the axial direction and are separated by thin porous walls. The channels are alternatively open at one end, but plugged at the other. The exhaust gases flow through the walls and escape through the pores in the wall material. Particulates, however, are too large to escape and are trapped in the monolith walls. The PCM starts the regeneration of the DPF if the soot load exceeds a performance map value. The PCM determines the load condition of the DPF based upon the exhaust gas pressure upstream and downstream of the DPF. A pressure differential sensor provides the pressure input to the PCM. During the regeneration process, the PCM raises the temperature in the DPF to burn off the soot accumulated. Under normal operation, the engine does not produce enough heat to oxidize the soot inside the DPF. This process requires temperatures above 550 ºC (1,022 ºF). After regeneration, the PCM reads the actual pressure difference at the DPF and compares it with a reference value. From this comparison, the PCM determines the ash quantity inside the DPF.
 
#12 ·
When I was out in the boondocks four-wheeling the other day, it occurred to me that I am doing lots of idling and very, very slow driving. What would I do if it said it needed regeneration? I was a couple hours from a highway.
 
#13 ·
Good question. How many hours were you off-roading? As that can give us some idea of how long we can go before getting an EVIC alert.

The obvious question is how much time, on average, do we have from the first EVIC message to limp mode. Jeep could answer that possibly--though Jeep would likely give you some "it varies widely based on ........" kind of answer.

I would make sure I had put in some highway time immediately prior to going wheeling to ensure starting out with a clean DPF.
 
#17 ·
Just for the record, when it tells you, you need to regen and drive to clear it... how far and long do you need to drive before cycle is complete? 5-10 miles? 15 min? or an hour ?? it would be good to know roughly if someone knows....:rolleyes:
 
#21 ·
Generally 15-20mins, the message on the screen should show you the progress, it will say 80%, then 70%, 60%, etc.
 
#25 · (Edited)
Its ok to interrupt an active regen that does not show an EVIC message. If you don't have an ODBII device to monitor exhaust temperature, you won't know you are interrupting anything. It happens all the time on all our GC diesels.

The problem arises when people don't operate at highway speeds for 20 minutes and the DPF fills beyond the normal levels....then you get the EVIC message. At that point DRIVE. Get it cleared out and all us well. If you ignore it and go on with your low speed driving, it will clog!

I have 12k miles on mine and have never seen an DPF warning. I suspect it takes a several days and a few hundred miles of low speed operation to fill the DPF enough to get the message.

Soon, someone will discover a method to trick the back pressure sensors and gut or remove the DPF....
 
#29 ·
If interrupted, I don't think regen starts again unless the DPF is filled above a certain threshold and speed requirements are met. If it burns down below that threshold, it waits until it goes above again. The threshold is probably well below the warning level. I wish there was a known OBDII parameter to see the back pressure sensors.
 
#39 ·
I am currently looking into purchasing an ecodiesel and would like to hear from anyone who drives primarily in the city. I live in NYC and am concerned about not being able to get enough highway driving during the week to clear out the DPF. Any advice would be helpful. Thanks!
 
#40 ·
I live in NYC and am concerned about not being able to get enough highway driving during the week to clear out the DPF. Any advice would be helpful. Thanks!
How many miles and how long does it take for your daily commute?

I'm not from New York but I have run mine exclusively in town for a whole week when I was off for the Holidays. We did a lot of shopping that week. The DPF is good for at least 6-10 hours of runtime without a regen by my estimation, maybe more. It is important after that to get above 45 mph for 20 minutes. Also, long warmups go against that time...so after 5 minutes, you'd want to go ahead and drive. IMO, if you don't drive at regen speeds and distances regularly, a modern diesel may not be the best choice. If you do, diesels are a great option.
 
#41 ·
Can or does the EVIC show the percentage full of the DPF ant any given moment, so that if you see it filling up you could plan a hwy trip in the next day etc to aviod limp mode? :confused:
 
#42 ·
Unfortunately there is no EVIC display except the final warnings which we now know means "drive NOW". You could possibly wait...but If you procrastinate, the DPF could fill up and your Jeep then goes into limp mode.

If you use an ODBII display device to monitor Exhaust Gas Temperature, you may notice 2 things before the DPF gets to the EVIC warning level. The EGT will be over 900°F steadily for more than a few seconds because its trying to regen often but can't. An ODBII warning code P02522 (I think) will set stating too many regens have been attempted. I saw this using the Torque App with no EVIC or other lights. This is all occurred on mine and I never got a warning because I finally let it finish its regen on a short highway run.
 
#46 ·
One other dumb question for the day...
If you do say a partial regen..( say for 10 of the 20 min potentially required.. then shut down or park somewhere...) Does that count towards getting a full regen done, or does it only work if you start and complete one 20 min cycle continuously....?
 
#48 ·
Since all this concern has arisen, I have began watching my EGTs for patterns that indicate the frequency and duration. The other day when mine was trying to regen in town every time I made a short trip, I finally drove on the interstate and the regen finished in 9 miles. I suspect each partial regen burned off some soot. I'll keep watching.
 
#49 ·
If there is a distinct pattern pre-mandatory-regen, theoretically we could write either a plugin or standalone app that could monitor the ODBII parameters and issue a warning. I've never written software for Android but I'd be happy to help however I can if/when I ever get my diesel.
 
#52 ·
As of now, I am in LIMP mode. Here is my sad story:

Got the first oil change done a few weeks ago, but the oil life countdown wasn't reset. "No biggie" says the guy with access to this site - I just looked up how to do it and...nuthin. Again and again I tried, and no change. I figured I'd live with it a while and keep trying the reset, and schedule a dealer visit in May as my own schedule was nuts, and again, it's just a countdown.

3 days ago, the CEL goes on, but no message or other notification. I thought that was odd, but as all it was telling me was to get an oil change, I figured there was a counter to the "oil life at 0%", and it was assuming I don't love my really expensive vehicle and was running on black tar.

Yesterday, the "Exhaust Filter getting full, safely drive at highway speeds" popped up. So I did - did about 9 miles at 70mph on the nearest interstate, and then turned around and did it again. While I was doing this, the message popped up twice. I found that incredibly odd.

Today, message still there, so did another 18 mile loop, but this time on another road at 55 mph, with stop lights. I took her out of eco, and enjoyed the torque off the line more than usual. Again, message kept popping up. I figured it HAD to go to a true regen at some point. Alas no. Parked it at Lowes not too far from the house, did some stuff, and went out to go for another drive...all hell broke loose 10 seconds after startup. FILTER FULL, SERVICE ELECTRONIC THROTTLE. Third gear only.

So now it is in the driveway, and I am going out of town on Tuesday. Oh, and Sunday is Easter.

Not pleased at the moment...
 
#53 ·
The Oil change reset is extremely important, it is tied to the DPF regen. If the system thinks it has old oil in there, it will react as such.

I would be super pissed at your dealer for failing to do this simple yet extremely important procedure during the service.
Get it towed to the dealer (Jeep Assist) and get them to fix it immediately as it is their fault.
 
#55 ·
does anyone know what is the most efficient speed and distance to drive is to complete a regeneration quickly and completely? Can you monitor it's completion some how by the EVIC?
 
#56 ·
The best conditions for regen are those that hold the highest steady exhaust temperatures. I get my highest readings (1250 °F) on flat ground at 50 mph but anything over 45 mph works.

The EVIC doesn't have any indication of regen. An ODB2 monitoring device such as the Scangauge II or Torque App for Android with a Bluetooth adapter will allow EGT monitoring.
 
#57 ·
That's not true, the EVIC can display the Regen in process. This is mentioned on the Diesel Supplement Owners Manual



 
#62 ·
OK. Here's what we know about the NAFTA version of the diesel:

1. The EVIC doesn't show a message during the normal regen process that we know is happening based on 1200°F EGTs we are seeing.

2. It has been verified that owners who drive too much in slow speed city conditions ARE seeing a regen warning. This is a final warning to allow a regen immediately. Most NAFTA Jeep owners will never see this.
 
#63 ·
Correct. That is not just a NAFTA thing, that is the worldwide process.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top