2015 Chevrolet Silverado 2500HD - P2002 DPF Efficiency Below Threshold

Question

My LML Duramax keeps throwing P2002. It seems like it's trying to regen every 50-100 miles now. I do a lot of highway driving so it should be getting plenty of heat to clean out the DPF. I'm worried the filter is actually cracked.

I looked at the soot grams on my monitor and they climb really fast even at steady speeds. There is no visible black smoke out of the tailpipe, which I heard is a dead giveaway for a cracked DPF, but the code keeps coming back after I clear it.

Ms_Torque · Accepted Answer

✅ Confirmed fix: Found a small exhaust leak at the flange before the DPF and a bad DPF Differential Pressure Sensor. The sensor was reading incorrectly, making the ECM think the soot load was higher than it actually was. Replaced the sensor and the plastic pressure lines that had become brittle. After a final forced regen, the pressure readings returned to normal and the code hasn't returned in 2,000 miles.

BMW_Bjorn · Answer

Before you replace the DPF, check the 9th injector (Hydrocarbon Injector) located in the exhaust downpipe. If it's clogged, the truck can't get enough fuel into the exhaust to actually burn the soot during a regen. It'll just keep trying and failing, which triggers the efficiency code.

2015 Chevrolet Silverado 2500HD - P2002 DPF Efficiency Below Threshold

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