Your 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 at the tailpipe. This lowers the exhaust temperature before it leaves the tailpipe.

The DPF, the tailpipe, or other exhaust system components must not be altered. The area where the exhaust cooler connects to the tailpipe should be inspected, especially the area where the fresh air enters the cooler. Make sure the openings are not restricted or plugged with mud or dirt which could inhibit exhaust gas cooling. See "Exhaust System Inspection" under At Least Twice a Year .

The DPF will regenerate (self-clean) itself as part of normal operation. During regeneration, the green DPF indicator is lit and you will notice a difference in engine noise and engine speed, but this is normal. The Engine Control Module (ECM) controls this function based on several factors including the amount of fuel consumed, hours of engine operation and miles driven.

Notice: Use of diesel fuel other than Ultra Low Sulfur Diesel (15 ppm sulfur maximum) or engine oil other than low ash CJ-4 oil will cause permanent damage to the DPF and related components. This damage would not be covered by your warranty.

Your DPF equipped vehicle has specific fuel and engine oil requirements. See What Fuel to Use and Engine Oil to make sure you use the required fuel and engine oil.

Caution: During DPF regeneration, the exhaust system and exhaust gases are very hot. Things that burn could touch hot exhaust parts under your vehicle and ignite. You or others could be burned. Do not park near or over papers, leaves, dry grass, or other things that can burn.

When the yellow DPF indicator comes on, the filter is dirty and DPF regeneration is necessary. When driving continues without regeneration, the DPF indicator will change from yellow to red. Continuing to drive the vehicle with the red indicator can cause filter damage.

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

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

Notice: Extended idle should be avoided because the DPF system is not capable of automatically regenerating at idle. During extended idle, be sure to watch for the DPF indicator lights which could come on to indicate that the DPF is becoming full and needs regeneration. If the yellow or red indicator light comes on, perform manual regeneration or drive the vehicle as described previously for automatic regeneration to clean the filter. Continued engine operation with the yellow or red DPF indicator light on, without performing manual or automatic regeneration, could cause irreversible damage to the DPF requiring repair and possible replacement that might not be covered by your warranty.

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.

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. This is normal. The by-product of combustion of engine oil is ash. 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 Modifications for important information.

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 regeneration.

When it is safe to do so, stop the vehicle. Perform manual DPF regeneration in a well ventilated area. Manual DPF regeneration must be performed outdoors, as follows. Once manual regeneration is started, complete the regeneration in a single operation if possible. If manual regeneration is not completed, as indicated by the green DPF indicator going off, and the yellow or red indicator light remains on, automatic regeneration might not be allowed until the vehicle is stopped and manual regeneration 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 regeneration, 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 is 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 PARK (P) or NEUTRAL (N).
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 Power Take Off (PTO), turn the PTO off. See Power Take-Off (PTO) .
8. Press the DPF switch on the instrument panel. See Instrument Panel Overview . The green DPF indicator light comes on, the exhaust gas control valve operates, engine idle speed automatically increases, and DPF regeneration begins. Do not leave the vehicle unattended during manual regeneration.
9. When both the green and the yellow or red DPF indicator lights go off, regeneration is completed. Regeneration is normally completed in about 30 minutes.

Under certain operating conditions, manual regeneration might not be able to be performed, even if the soot level in the DPF requires regeneration. This can occur because of low coolant temperature, low battery voltage, or high exhaust temperature or immediately after starting the vehicle. When manual regeneration is requested, by pressing the DPF switch, when coolant temperature is low, engine warm-up is started, the green DPF 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, regeneration will start.