P2002 fault code: Particulate Trap Efficiency Below Threshold

Last updated · OBDCode UK editorial

Self-drawn engine management and DPF lamps for P2002 particulate trap efficiency
Decorative labelled telltales: the engine management light and a diesel particulate-filter lamp that P2002 may set. Both are usually amber. This drawing is not manufacturer artwork and does not claim a red lamp.
Can I drive with P2002? — Limited driving

Short essential trips may be possible if the engine runs normally and there is no exhaust smell in the cabin. Stop if power falls away, smoke worsens, or fumes enter the car.

P2002 means “Particulate Trap Efficiency Below Threshold” — an extended powertrain range fault in the powertrain. Limited driving. The engine computer thinks the diesel particulate filter is not trapping soot as well as it should. This is an emissions fault. It does not authorise cutting out the filter or a home forced regeneration.

Can I DIY?

Caution — conditions apply. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage.

Caution — conditions applyDIY boundary
ToolsBasic tools only — for example a household socket set, tyre gauge, or a consumer OBD reader.

Some checks may be possible for a careful DIY driver with the right tools and a safe place to work. Stop if anything feels beyond your skill or kit.

Hot systems

Never open a hot coolant cap — pressure can scald you. Exhaust and catalytic converter get hot enough to burn and ignite debris. Stay clear of electric fans; they can run after shut-off.

P20xxExtended powertrain range
MOT fail riskif the warning light stays on

What does P2002 mean?

P2002 is a powertrain code from the extended SAE range reported by your car’s engine control unit. It sits in the P20xx block, which covers extended powertrain range. The stored description is “Particulate Trap Efficiency Below Threshold”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

How to diagnose P2002 yourself

  1. Confirm P2002 and freeze-frame: Scan with an OBD-II reader while the car is parked in open air. Record whether P2002 is current or pending, freeze-frame distance and temperature, and any companion diesel-filter codes. Stop if: You also have a flashing engine management light, exhaust smell in the cabin, or an overheat warning.
    Generic driver footwell showing a broad OBD-II socket search zone and the usual 16-pin socket shape.
    Park safely and switch off before locating the socket. Its position varies, so use the vehicle handbook and never force or dismantle trim.
  2. Note DPF lamp versus engine light: With ignition on, record whether a dedicated DPF or soot lamp is lit, flashing, or off, and whether the engine management light is steady. Do not clear lamps to ‘see if they return’ before the garage sees them. Stop if: Fumes in the cabin, dizziness, or a flashing engine management light — get fresh air and do not keep idling.

Will P2002 fail an MOT?

An illuminated engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off. Testers also inspect whether a diesel particulate filter is missing, obviously incomplete or leaking.

Before booking your test, check what usually fails on your car: see our MOT pass rates by make and model, built from 33.1 million DVSA tests.

What the MOT data says

These figures are copied from the MOT fail cohort for the certificate wording below. They are not a diagnosis of this car.

Certificate wording: “Particulate filter Emission control equipment fitted by the manufacturer missing, obviously modified or obviously defective”.

Of 1,351 Class 4 vehicles that failed a 2024 MOT on that wording, 0.89% (95% CI 0.5–1.5) failed on the same wording again in 2025. The not-tested gap versus control was 15.3 points.

Related guides

Car diagnostic test cost: compare the scopeUK booking marketplaces currently publish diagnostic averages of about £52–£65. Engine management light on: steady or flashing?A steady engine management light means the computer has stored a fault. Drive with caution and get the code read. A flashing light is different — stop when it is safe. DPF light still on after driving: stop repeating the runCan I drive? No—not for another clearing run. If the DPF light stayed on after the handbook journey, park and arrange diagnosis. A red or flashing warning, power loss, smoke or… DPF cleaning cost: what a quote should proveAsk for soot, ash and pressure evidence and the fault that prevented regeneration before authorising work.
P2000NOx Trap Efficiency Below Threshold P2001NOx Trap Efficiency Below Threshold P2003Particulate Trap Efficiency Below Threshold P2004Intake Manifold Runner Control Stuck Open P2005Intake Manifold Runner Control Stuck Open P2006Intake Manifold Runner Control Stuck Closed P2007Intake Manifold Runner Control Stuck Closed P2008Intake Manifold Runner Control Circuit/Open

P2002 — quick answers

Is it safe to drive with P2002?

Limited driving. Short essential trips may be possible if the engine runs normally and there is no exhaust smell in the cabin. Stop if power falls away, smoke worsens, or fumes enter the car.

Can I fix P2002 myself?

Caution — conditions apply. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage. Basic tools only — for example a household socket set, tyre gauge, or a consumer OBD reader.

Will P2002 fail my MOT?

An illuminated engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off. Testers also inspect whether a diesel particulate filter is missing, obviously incomplete or leaking.

Fault-code identifiers are standard diagnostic facts. Their explanations and diagnostic guidance on this site are original editorial summaries, not reproduced SAE wording. MOT defect rules reflect the DVSA MOT inspection manual (2026). This page is general guidance for UK drivers, not a substitute for a professional diagnosis.