P2002 how serious

[KGrierson]

Have code showing up twice in last week with onlt 2500miles on truck. Wonderig what anybody thinks

 

[Alan Reagan]

You probably need to take a good long trip. That's the DPF efficiency code. The DPF needs a good hard run to get it hot and clean it out. Otherwise, you will be having it cleaned out.

 

[Bob4x4]

There is a list of possibilities-driving it harder will NOT fix it

 

[Alan Reagan]

Driving hard may not solve it. If there is a cold air intake on the truck or the EGR is not working properly, these can both cause the DPF to start clogging. The reason I said to run the truck was because of how the system is working.



OPERATION

The oxidation catalyst raises 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 ECM 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. The catalyst contains a large number of 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 ECM starts the regeneration of the DPF if the soot load exceeds a performance map value. The ECM determines the load condition of the DPF based upon the exhaust gas pressure upstream and downstream of the DPC/DPF. A pressure differential sensor provides the pressure input to the ECM. During the regeneration process, the ECM raises the temperature in the DOC/DPF to burn off the soot accumulated. Under normal operation, the engine does not produce enough heat to oxidize the soot inside the DOC/DPF. This process requires temperatures above 550°C (1,022°F). After regeneration, the ECM reads the actual pressure difference at the DOC/DPF and compares it with a reference value. From this comparison, the ECM determines the ash quantity inside the DOC/DPF.



So with a differential pressure exceeding a certain threshold, usually the DPF is not burning off enough. And efficiency is not adequate.



I didn't see what year the truck is or if any mods have been made, specifically a cold air intake.



Also, there was a TSB for a reflash on the 2010 model to correct this problem.



Finally, towing or running at least 45 minutes of interstate will give the truck a good chance to have an effective regen. If that doesn't work, then the DPF will probably have to be cleaned.

 

[lksmitty]

There is a new ECM flash for the problem that came out recently. My 2011 was throwing the same code and I haven't had any problems since they updated the ECM.

 

[KGrierson]

You hit it right on the head. Took truck in,thats exatly what they did.

 

[Alan Reagan]

Glad you got it corrected. I knew there was a 2010 TSB for the reflash but hadn't seen it carried over to 2011.