P2002 indicates the engine control module has detected that the diesel particulate filter (DPF) on bank 1 is not trapping soot efficiently enough to meet emissions thresholds. The determination is based on pressure differential across the filter and/or soot load models compared to expected values.
The filter is clogged with ash or soot beyond regeneration capability, or the substrate is cracked/melted, preventing proper filtration.
A leak before the filter reduces exhaust pressure differential, causing the control module to calculate false low efficiency.
The sensor or its reference hoses provide incorrect delta-P readings, leading to an erroneous efficiency calculation.
Short-trip driving, faulty glow plugs, EGR issues, or software calibration can prevent the DPF from reaching regeneration temperature.
Incorrect temperature data prevents proper regeneration timing and soot-load modeling.
Rare; outdated calibration may misinterpret sensor data, but hardware faults are far more common.
The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:
Removing or defeating the DPF is illegal for on-road use in most jurisdictions and will cause the vehicle to fail emissions inspections. It also voids warranties and may increase tailpipe emissions significantly.
No. Control module failure is an extremely rare cause. The code almost always points to a physical DPF issue, exhaust leak, sensor fault, or regeneration problem. Replace the PCM only after all other causes are conclusively ruled out.
A forced regeneration may clear the code temporarily if the filter was only moderately loaded. If the DPF is near its ash limit or physically damaged, the code will return because the filter can no longer achieve target efficiency.
Not necessarily. First confirm there are no exhaust leaks, sensor faults, or regeneration-preventing conditions. If the filter is mechanically intact and below its ash capacity, a successful regeneration may restore efficiency.