Oxidation Catalytic Converter and Diesel Particulate Filter System
WARNING
The normal operating temperature of the exhaust system is very high. Never work around or attempt to repair any part of the exhaust system until it has cooled. Use special care when working around the diesel oxidation catalytic converter or the diesel particulate filter. The diesel oxidation catalytic converter and the diesel particulate filter heat up to very high temperatures after only a short period of engine operation and remain hot after you switch the engine off.

Your vehicle has a diesel particulate filter. The diesel particulate filter is an inline filter in the exhaust system that reduces carbon emissions by trapping exhaust particles before they reach the tailpipe. The diesel particulate filter looks similar to a traditional exhaust catalyst and is part of the exhaust system under your vehicle. The filter couples to a diesel oxidation catalyst that reduces the amount of harmful exhaust emitted from the tailpipe. As soot gathers in the system, it begins to restrict the filter. The system must periodically clean the soot that gathers inside the filter. This is carried out in two ways, passive regeneration and active regeneration. Both methods occur automatically and require no actions from the driver. During either one of these regeneration methods, although you may notice a change in exhaust tone. At certain times, the information display shows various messages related to the diesel particulate filter. See  Information Messages
Diesel Particulate Filter Maintenance
You must properly maintain your vehicle's diesel particulate filter in order for it to function properly.
Do not disregard maintenance messages that appear in the information display. Failure to follow the instructions of an information message may degrade vehicle performance and could lead to engine damage that may not be covered by the vehicle Warranty.
Failure to perform active or operator commanded regeneration when instructed could result in a clogged diesel particulate filter. If the diesel particulate filter fills beyond the regeneration threshold, your vehicle disables the ability for active and operator commanded regeneration. This could result in irreversible damage to the diesel particulate filter requiring replacement that may not be covered by the vehicle Warranty.
Passive Regeneration
In passive regeneration, the exhaust system temperature and constituents automatically clean the filter by oxidizing the soot. Cleaning automatically occurs during normal vehicle operating conditions due to driving patterns.
Active Regeneration
Once the diesel particulate filter is full of exhaust particles, the engine control module commands the exhaust system to clean the filter through active regeneration. Active regeneration requires the engine computer to raise the exhaust temperature to eliminate the particles. During cleaning, the particles convert to harmless gasses. Once cleaned the diesel particulate filter continues trapping exhaust particles.
The regeneration process operates more efficiently when you drive your vehicle at a constant speed above 30 mph (48 km/h) and at a steady engine speed for approximately 20 minutes. The frequency and duration of regeneration fluctuates by how you drive your vehicle, outside air temperature and altitude. For most driving, regeneration frequency varies from 100–500 mi (160–805 km) between occurrences and each occurrence lasts 9–35 minutes. You can usually reduce the duration of regeneration if you maintain a constant speed above 30 mph (48 km/h).
When the engine control module detects that the diesel particulate filter is nearly full of particulates and you are not operating your vehicle in a manner to allow effective automatic regeneration, messages appear in the information display as a reminder for you to drive your vehicle in order to clean the diesel particulate filter. If you drive your vehicle in a manner to allow effective automatic regeneration, the information display shows a cleaning exhaust filter message, which is the normal regeneration process. You can also choose operator commanded regeneration to clean the exhaust system at this point. See  Information Messages
If you are not able to drive in a manner that allows effective automatic active regeneration or you choose to perform regeneration of the diesel particulate filter while at idle, then operator commanded regeneration would need to be performed.
Operator Commanded Regeneration (If Equipped)
If your vehicle is operated with significant stationary operation, low speed drive cycles less than 25 mph (40 km/h), short drive cycles, a drive time is less than 10 - 15 minutes or the vehicle does not fully warm up, passive and active regeneration may not sufficiently clean the diesel particulate filter system. Operator commanded regeneration allows you to manually start regeneration of the diesel particulate filter at idle to clean the filter. If you are not sure whether your vehicle has this feature, contact an authorized dealer.
When to Carry Out Operator Commanded Regeneration
You can use the operator commanded regeneration feature when a message appears in the information display and you are not able to drive in a manner that allows effective automatic active regeneration or if you choose to manually start the regeneration of the diesel particulate filter manually while the vehicle is idle. See  Information Messages
Operator Commanded Regeneration Precautions and Safe Exhaust Position
WARNING
Do not park or idle your vehicle over dry leaves, dry grass or other combustible materials. The regeneration process creates very high exhaust gas temperatures and the exhaust will radiate a considerable amount of heat during and after regeneration and after you have switched the engine off. This is a potential fire hazard.
Stay clear of the exhaust tailpipe during regeneration. Hot exhaust gases can burn you badly.

Make sure that the louvers located at the tip of the exhaust are clear of any obstructions as they are used to introduce fresh air into the tailpipe to cool the exhaust gases as they leave the exhaust system.
Before you start operator commanded regeneration, do the following:
  • Shift into park (P) or if you have an RNDM selector shift into neutral (N) and apply the parking and or air brake, on stable, level ground.
  • Park your vehicle outside of any structure.
  • Park your vehicle 10–15 ft (3–5 m) away from any obstructions and away from materials that can easily combust or melt, for example paper, leaves, petroleum products, fuels, plastics and other dry organic material.
  • Make sure there is a minimum of 1/8 tank of fuel.
  • Make sure all fluids are at proper levels.
How to Start Operator Commanded Regeneration
WARNING
Stay clear of the exhaust tailpipe during regeneration. Hot exhaust gases can burn you badly.

Note:  You cannot use the operator commanded regeneration until the diesel particulate filter load percentage has reached 100%. The diesel particulate filter load percentage fluctuates up and down when driving your vehicle due to active and passive regenerations.
Note:  During the use of operator commanded regeneration, you may observe a light amount of white smoke. This is normal.
Missing Image  You may not be able to use operator commanded regeneration if the service engine soon warning lamp appears in the information display
Information Display Procedure
Start with your vehicle engine and when it has reached the normal operating temperature, press the information display control button on the steering wheel. See  General Information.  If a message advising that the exhaust filter is full appears in the information display, press the OK button to set the display to Y. Answer yes to this prompt and then follow the next prompts regarding exhaust position required to initiate operator commanded regeneration. Be sure to understand each prompt. If you are not sure what is being asked by each prompt, contact an authorized dealer. The display confirms the operation has started and when it has finished.
If the diesel particulate filter is near or at saturation, a message requesting permission to initiate filter cleaning appears in the information display. See  Information Messages.  Answer yes to this prompt and then follow the next prompts regarding exhaust position required to initiate operator commanded regeneration. Be sure to understand each prompt. If you are not sure what is being asked by each prompt, contact an authorized dealer. The display confirms the operation has started and when it has finished. You can also drive to clean the filter.
Missing Image  When the system is at the point of oversaturation, the service engine warning lamp illuminates and a message appears in the information display. You cannot initiate filter cleaning. You must have your vehicle checked as soon as possible.
Once operator commanded regeneration starts, engine speed increases to approximately 2000–2500 rpm and the cooling fan speed increases. You will hear a change in audible sound due to engine speed and cooling fan speed increases.
It is not necessary to open the hood on the engine compartment. Once operator commanded regeneration completes, the engine speed returns to normal idling. The exhaust system remains very hot for several minutes even after regeneration is complete. Do not reposition the vehicle over materials that could burn until the exhaust system has had sufficient time to cool. Depending on the amount of soot collected by the diesel particulate filter, ambient temperature and altitude, operator commanded regeneration lasts approximately 30 minutes.
Operator Commanded Regeneration with Automatic Regeneration Control (If Equipped)
If your vehicle is operated with significant stationary operation, low speed drive cycles less than 25 mph (40 km/h), short drive cycles, drive time less than 15 minutes or the vehicle does not fully warm up, passive and active regeneration may not sufficiently clean the diesel particulate filter system. You can switch off automatic regeneration until better driving conditions are available, for example steady high speed driving. You can then switch automatic regeneration back on to clean the diesel particulate filter.
Switching Automatic Regeneration Control On and Off
To switch operator commanded regeneration on and off, use the information display control on the steering wheel. See  General Information.  Scroll to the exhaust cleaning message and then select Y or N to switch it On or Off.
How to Interrupt or Cancel Operator Commanded Regeneration
If you need to cancel the operator commanded regeneration, pressing the brake, accelerator or switching the engine off stops the procedure. Depending on the amount of time you allowed the operator commanded regeneration to operate, soot may not have had sufficient time to be fully eliminated, but the exhaust system and exhaust gas may still be hot. If you shut your vehicle off during operator commanded regeneration, you may notice turbo flutter. This is a normal consequence caused by shutting off a diesel engine during boosted operation and is considered normal.
Filter Service and Maintenance
Over time, a slight amount of ash builds up in the diesel particulate filter, which is not removed during the regeneration process. The filter may need to be removed for ash cleaning at approximately 120000 mi (190,000 km) or it may need to be replaced with a new or remanufactured part. Actual mileage varies depending on engine and vehicle operating conditions. The filter may need to be replaced with a new or remanufactured part at approximately 250000 mi (400,000 km). Actual mileage varies depending on engine and vehicle operating conditions.
Missing Image  If filter service is required, the engine control system warning lamp illuminates in the information display.Missing Image  Missing Image  If there are any issues with the diesel particulate filter system, the engine control system warning lamp and a service engine soon warning lamp illuminate to inform you that your vehicle requires service. Have your vehicle checked as soon as possible.
Resonator and Tailpipe Assembly Maintenance
Aftermarket devices or modifications to the exhaust system may reduce the effectiveness of the exhaust system as well as cause damage to the exhaust system or engine. This may also degrade vehicle performance and could lead to engine damage that may not be covered by the vehicle Warranty.