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Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
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2007 gmc: duramax..exaust..engine in reduced power mode how do you

Resolved Question:

2007 gmc duramax exaust filter needs to be cleaned engine in reduced power mode how do you clean it
Submitted: 9 years ago.
Category: Chevy
Expert:  Bob replied 9 years ago.
Diesel Particulate Filter Information on exhaust filter (DPF) below thanks. If cleaning fails and light stays on, you may need to replace filter and have codes cleared with a scan tool.

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.

The DPF will regenerate (self-clean) itself as part of normal operation. 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. On average, the DPF will clean itself about once per tank of fuel.

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.

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.

If you have a pickup model and the CLEAN EXHAUST FILTER SEE OWNERS MANUAL NOW message appears in the Driver Information Center (DIC), the DPF needs to be cleaned. If you have a van model and the engine exhaust gas filter warning light, CLN EXH FILTER, comes on, the DPF needs to be cleaned.

To clean the filter, drive the vehicle above 30 mph (50 km/h) until the warning light/message goes off. This will take about 20 minutes.

Notice: Extended idle should be avoided because the DPF system is not capable of regenerating at idle. During extended idle, be sure to watch for the DPF warning light/message which could come on to indicate that the DPF is becoming full and needs regeneration. If the light/message comes on, stop the idling and drive the vehicle as described previously to clean the filter. 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 your warranty.

Extended idling in PARK (P) can cause exhaust parts and gases to become very hot. Keep the exhaust area clear of material that could ignite or burn.

The DPF warning light/message comes on when the DPF is dirty and needs regenerating. You will also notice a change in the exhaust sound and engine idle speed. This is normal.

If you continue to drive with the DPF warning light/message on and the exhaust filter is not cleaned as required, the check engine and reduced engine power warning lights will come on and dealer/retailer service is necessary.

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.


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