He has stated that there is a P2002 fault and this is a bad DPF but I believe there are other things that can cause this code also. Diagnostic flow chart is a little vague for this code.
Good ol' 2002. There is a stupid number of problems that can cause this code. The book is vague because the code is determined by a logorithm in the ecu. There are many factors, many on the engine side.
Some notes on the DPF: When the engine is running, three things end up at the DPF, exhaust gas, soot, and ash. The gas passes through, soot and ash don't. Soot turns into gas during regen, but ash remains. Ash buildup will eventually plug an otherwise good DPF. That's what this 'pin test' is, as mentioned by the dealer. A piece of wire (something like 0.4mm dia.) is run down into the substrate, and the length needs to be above x amount, x being some number that would require lots of digging, because I have no idea off the top of my head. Theoretically, if the ash level is too high, it will limit the amount of soot that's able to be caught, and the result will be regens needed that are too frequent, and the ecu picks up on this. I'd ignore the pin test right now and rule everything else out first.
So, you have a low power problem with no codes (other than P2002)? That's annoying. There are a few things that can cause this. How much oil is the turbo passing? They all do it, but some are much worse than others. Some oil naturally comes from the breather, and a coalescing filter and different cap can be added (from an 11-13 truck) to help condense the oil vapor back into oil, keeping it out of the turbo intake. If the turbo intake is relatively clean, but oily goo is coming out of the compressor outlet and ending up in the intercooler, this can be a problem. Given enough time, the goo effectively blocks much of the core, starving the engine of air. Take the black outlet hose off of the cooler, start the truck, and hold the accelerator to the floor. A huge torrent of air should blast out. If it seems anemic for any reason, Take the intercooler off and send it to a machine shop that has a hot tank with aluminum-safe cleaner, like Penmul or Oakite, and have it soaked for several hours. Flush it with a torrent of hot water. Put it back on the truck with outlet hose off, start it, hold it to the floor to blow out any debris, and try it again. A clogged air filter, a turbo with excessive shaft play (especially axial play) and any boost leaks can also lead to reduced airflow.
These trucks use EGR, and sometimes the intake tract gets slam full of carbon. Remove the power steering reservoir and mounting bracket and remove the intake elbow, and look inside the intake. I've seen half the diameter of the intake ports covered with caked on carbon. Get one of the PM lackeys to dig all that gunk out of there, taking care not to mash it all into the intake ports.
Back to the DPF: If the two differential pressure tubes are clogged or leak, it will throw the delta pressure reading off. Take the tubes off of the sensor and blow compressed air through them. Check carefully for cracks or holes. Carefully check the harness side of the temp sensors for damaged wires. The front sensor especially, it's subject to more vibration or something than the rear, and the wires sometimes break. You may have to load test the circuit with a headlight bulb. Do a regen to see if the temp readings are realistic. If one periodically does something stupid like go to -400F, then you know there's a problem.
Check the exhaust brake setting (important). Engine at operating temp, use activation test to hold at 980 rpm, take injection quantity reading (should be at least 7mm3, any less indicates injector problem, which will plug a DPF), then turn on exhaust brake. It should shoot up to mid twenties. The difference should be 14mm3. You'll see two limiter adjustments. Don't mess with the one that the arm rests on with the exhaust brake off, only adjust the one that the arm rests on with the brake on. To lower exhaust brake injection quantity, unscrew bolt, which will limit travel of arm.
If the intake throttle valve does not have three small holes drilled in it, it needs to be modified. If it does, then check for play. Only acceptable movement is the twisting motion to open and close it. Any front-rear or side-to-side play means it's worn out.
Don't over fill with oil. It turns to ash and plugs DPF.
Fuel dilution? Check injector return pipe for leakage. Very important, this blows these engines up. Absolutely consult the manual when messing with this thing. I posted a procedure earlier.
Gotta go, have fun!
