Cummins ISX DOC REPLACEMENT

DOC does not last forever and will need to be replaced at some point in time. 600k miles is still somewhat young, but it depends on how healthy of a life it had. The DPF will need to be cleaned every so often, but should only be replaced if needed. During cleaning, they can measure how easily air flows through. There are specs for this. If it develops too much back pressure it is junk. It is not a "good idea" to just replace one on a whim. It should be tested/cleaned. If not already, you will find out they are very expensive!!!

 

If everything is coming apart, I wouldn't be afraid to replace the sensors though. They do take a beating during disassembly.

 

I would replace the DOC. There is no test to check the health of the DOC catalytic performance once it is removed. All you can do is look at it and see if it is damaged. If there are regen temp issues and troubleshooting pin point a lazy DOC, then replace it. The DPF only gets more and more plugged throughout it's life. It can be successfully baked and cleaned out and returned to service. You need to make sure there are no cracks and it still passes the DPF flow test I described before. I would send it out to be cleaned and tested. If it is ok to reuse, then reuse it! No need to spend a couple thousand bucks if you don't need to. I would replace the sensors and have a new aftertreatment injector installed. Weak or lazy aftertreatment injectors are one part that can lead to this trouble in the first place.

 

The DOC is generally a bit more expensive than the DPF. But they are close to the same cost. DPFs are cleaned in specific cleaning machines. These machines are very expensive, and so not every shop has them. It depends on your location as to who has one and how far away they are. For a full cleaning, it takes a full bake. Full bakes take 8 to 12 hours to complete depending on the type of cleaning machine. Depending on all that you could expect it to take 24-48 hours to get back.

 

You can try that, for sure.

 

Get both cleaned and check the exhaust piping , from the turbo to the after treatment filters . There is a flex pipe 2-3 feet behind turbo that will leak and throw a doc code . Best way to see if it's leaking , do a park'd regen ,if you see white smoke under cab it's leaking