Particulate Filter Efficiency Below Threshold Bank 1
The P2002 code indicates that the Diesel Particulate Filter (DPF) on Bank 1 is not operating at its required efficiency level to reduce soot emissions. The Powertrain Control Module (PCM) sets this code when it detects that the exhaust pressure or temperature readings across the DPF do not match expected values, implying the filter is damaged, missing, or failing to trap particulate matter.
While the vehicle can usually still be driven, ignoring this code can lead to reduced engine performance or a forced 'limp mode'. It should be diagnosed soon to prevent further damage to the exhaust system or engine.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Decreased engine performance or sluggish acceleration
- Vehicle entering 'limp mode' (reduced power)
- Decreased fuel economy
- Excessive black smoke from the exhaust (in severe cases)
Likely causes
- Damaged or degraded Diesel Particulate Filter (DPF)
- Faulty DPF pressure sensor or clogged sensor tubes
- Exhaust leaks before or near the DPF
- Faulty exhaust gas temperature (EGT) sensor
- Use of incorrect or high-sulfur diesel fuel
- Aftermarket exhaust modifications (DPF delete or hollowed filter)
What to check before replacing parts
Scan for additional codes and check freeze frame data.
Look for: Look for related codes (like EGT or pressure sensor codes) that might indicate a sensor failure rather than a failed DPF.
Visually inspect the DPF and surrounding exhaust pipes.
Look for: Look for signs of physical damage, severe discoloration from overheating, or exhaust soot leaks indicating a cracked pipe or loose flange.
Inspect the DPF pressure sensor hoses and tubes.
Look for: Check for cracked, melted, or clogged rubber hoses or metal tubes connecting the DPF to the pressure sensor, which can cause false readings.
Monitor DPF pressure sensor data using a scan tool while driving.
Look for: Compare the actual differential pressure across the DPF to the manufacturer's specifications; a reading that is too low indicates a hollowed or cracked filter.
Perform a forced DPF regeneration using a bidirectional scan tool.
Look for: Observe if the regeneration process completes successfully and if the pressure differential returns to normal, which may clear the code if it was a temporary anomaly.
This page explains the generic P2002 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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