2017 Audi Q7 - P2002 Particulate Trap Efficiency Below Threshold

Question

Driving my Q7 TDI yesterday and the DPF light came on, followed by the glow plug light flashing and the car going into limp mode. I pulled P2002. I tried driving it on the highway at 3000 RPM for 20 minutes to trigger a regen, but it won't clear.

Soot load is showing 35g on my VCDS. The car has 85k miles. I'm worried the DPF is actually cracked or completely plugged. Has anyone had luck with the off-car cleaning services or is it time for a new filter?

ReganRegen · Accepted Answer

✅ Confirmed fix: The DPF was internally cracked. I checked the tailpipe with a white glove and it came back covered in black soot—on a functional DPF, the tailpipe should be clean. A cracked substrate allows soot to bypass the filter, triggering the efficiency code. Had to replace the DPF assembly and the downstream NOx sensor which was also fouled by the soot.

DPF_Doc · Answer

Often, P2002 on these 3.0 TDIs isn't a bad DPF, but a bad Exhaust Pressure Sensor (G450). If the sensor sends a skewed reading, the car thinks the DPF is failing its efficiency test. Check the two rubber lines going to the sensor for melt spots or cracks first.

2017 Audi Q7 - P2002 Particulate Trap Efficiency Below Threshold

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