P2002: Diesel Particulate Filter Efficiency Below Threshold (Bank 1)

What does P2002 mean?

P2002 means the particulate filter on bank 1 lets too much soot through, typically because the substrate is cracked, partly melted, emptied or bypassed. CARB requires diesel OBD to flag a filter whose filtering performance lets PM emissions exceed the limit. Older systems judge this from the pressure drop: GM's 2009 Duramax compares the flow resistance shortly after a regeneration (within 600 s or 18.6 miles, soot load at most 40 g) with a table and aims at a filter leaking eight times the standard. Newer systems use a resistive PM sensor behind the filter: on the 2014 Cruze 2.0 diesel, GM's 2018 diesel group and Ford's 2023 diesels the code sets when the sensor current exceeds 12 µA before the modelled amount of soot needed to trigger an intact sensor has passed. Ford names cracked substrates on Transit 3.2, F-150 3.0 and Super Duty 6.7 and replaces the filter; GM states that a filter with P2002 cannot be cleaned by service regeneration. Regenerating does not cure it.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Malfunction indicator lamp on
• Usually no change in driveability
• Visible soot at the tailpipe in severe cases

Common causes

• High Filter substrate cracked or melted, often after an uncontrolled regeneration
• Medium Filter removed, emptied or bypassed
• Medium Faulty differential pressure sensor or leaking sensor hoses on pressure-based systems

Likelihood is a general estimate across vehicles; your make and model may differ.