The vehicle has a Diesel Particulate Filter (DPF) as part of the exhaust system to reduce vehicle emissions. The DPF requires a unique exhaust tailpipe with an exhaust cooler. The exhaust cooler mixes air with the exhaust to lower the temperature before it leaves the tailpipe.

The DPF, the tailpipe, or other exhaust system components must not be altered. Inspect regularly and clean any mud or dirt from the exhaust cooler, especially where the exhaust cooler connects to the tailpipe and the openings where fresh air enters the cooler. See "Exhaust System Inspection" under At Least Twice a Year.

The DPF will clean itself as part of normal operation. Several factors including fuel consumed, hours of engine operation and miles driven are monitored by the Engine Control Module (ECM). The self cleaning occurs approximately once per tank of fuel.

During self cleaning, the green DPF indicator light will come on. See Diesel Particulate Filter Warning Light.

To clean the filter, either drive the vehicle above 30 mph (50 km/h) to activate self cleaning, or stop the vehicle and perform the manual cleaning procedure. For self cleaning, drive until the green DPF indicator light goes off. This will take approximately 20 minutes. Once self cleaning has started, drive until the green indicator light goes off to complete the cleaning in a single operation if possible.

Extended idling can cause exhaust parts and gases to become very hot. Keep the exhaust area clear of material that could ignite or burn. See Parking Over Things That Burn for more information.

Caution: During DPF self cleaning or during extended idling in P (Park), the exhaust system and exhaust gases are very hot. Things that burn could touch hot exhaust parts under the vehicle and ignite. You or others could be burned. Do not park, or idle for an extended period of time, near or over papers, leaves, dry grass, or other things that can burn. Keep the exhaust area clear of material that could ignite or burn. See Parking Over Things That Burn for more information.

Notice: Extended idle should be avoided because the DPF system is not capable of self cleaning at idle. During extended idle operation, monitor the instrument panel telltale lights and Driver Information Center for messages and take appropriate indicated action. Continued idling with the warning light/message on could cause irreversible damage to the DPF requiring repair and possible replacement that might not be covered by the vehicle warranty.

When the yellow DPF indicator comes on, the filter is dirty and needs cleaning. You will also notice a change in the exhaust sound and engine idle speed. This is normal. If you continue to drive and the exhaust filter is not cleaned as required, the DPF indicator will change from yellow to red. Continuing to drive the vehicle with the red indicator can cause filter damage.

Vehicles with DPF have specific fuel and engine oil requirements. See What Fuel to Use and Engine Oil for more information on those requirements.

Notice: Permanent damage can occur to the DPF or related components if the required Ultra Low Sulfur Diesel (15 ppm sulfur maximum) or low ash CJ-4 engine oil is not used. This damage would not be covered by the vehicle warranty.

For vehicles with Power Take-Off (PTO), monitor the instrument panel cluster for lights related to the DPF.

All engines consume some amount of engine oil. Ash is the by-product of engine oil consumption. The ash will become trapped in the DPF over the life of the vehicle. Eventually, the buildup of ash will restrict the exhaust gases and the DPF will need to be cleaned or replaced.

See Accessories and Modificationsfor important information if you are considering adding accessories or modifying the vehicle.

Caution: During DPF self cleaning, the exhaust system and exhaust gases are very hot. Stay clear of the tailpipe area and do not park over things that burn. You or others could be burned or the vehicle could catch fire. See Parking Over Things That Burn.

If the yellow or red DPF indicator is on, you can clean the DPF by performing a manual cleaning.

When it is safe to do so, stop the vehicle. Perform DPF manual cleaning in a well ventilated area. DPF Manual cleaning must be performed outdoors, as follows. Once manual cleaning is started, complete the manual cleaning in a single operation if possible. If manual cleaning is not completed, as indicated by the green DPF indicator going off, and the yellow or red indicator light remains on, self cleaning might not be allowed until the vehicle is stopped and manual cleaning is performed until completed.

1. Check engine oil and engine coolant levels to be sure they are at proper operating levels.
2. To prevent running out of fuel during manual cleaning, make sure there is at least a quarter of a tank of fuel.
3. Check to make sure the area near the exhaust tailpipe and under the exhaust system are clear of any materials that could catch fire. Keep people away from the area of the exhaust system and exhaust gases.
4. Fully set the parking brake.
5. Shift the transmission to P (Park) or N (Neutral).
6. Idle the engine. If you used the idling control knob to increase the engine speed, restore it all the way to the left to reduce the engine speed.
7. If the vehicle has a Power Take Off (PTO), turn the PTO off. See Power Take-Off (PTO).
8. Press the DPF switch in the instrument panel switchbank. See Instrument Panel Switchbank. The green DPF indicator light comes on, the exhaust gas control valve operates, engine idle speed automatically increases, and DPF cleaning begins. Do not leave the vehicle unattended during manual cleaning.
9. When both the green and the yellow or red DPF indicator lights go off, cleaning is completed. Manual cleaning is normally completed in about 30 minutes.

Under certain operating conditions, manual cleaning might not be able to be performed, even if the soot level in the DPF requires cleaning. This can occur because of low coolant temperature, low battery voltage, high exhaust temperature or immediately after starting the vehicle. When manual cleaning is requested and coolant temperature is low, an engine warm-up cycle is started. The green indicator light will come on, the exhaust gas control valve operates, and engine rpm increases to help raise engine coolant temperature. When operating conditions allow, cleaning will begin.