AI-powered OBD-II fault code diagnostic tool for UK drivers
P2002

P2002 Diesel Particulate Filter Efficiency Below Threshold (Bank 1)

P2002 indicates diesel particulate filter efficiency below threshold (bank 1). The exact repair depends on whether the underlying issue is a sensor fault, wiring problem, mechanical wear, or a related system problem on the vehicle being diagnosed.

Last reviewed 14 June 2026 AI-Diagnostics-Pro Editorial Team

This guide is reviewed against current UK fault-code usage patterns, MOT guidance, and indicative repair-cost context. It is educational guidance for P2002, not a substitute for live data, workshop testing, or a final quote.

Editorial policy UK MOT guide DVSA MOT inspection manual
UK Repair Cost
£100–£1500
MOT Risk
High risk of MOT failure
Safe to Drive?
Try a DPF regeneration run (30 min motorway at 60mph+) first. If the light stays on, get it diagnosed.

At a glance: P2002 for UK drivers

Fault family
Diesel aftertreatment and AdBlue
Best first check
Ask about recent driving style before replacing any DPF parts.
Typical garage risk
A blocked DPF is often treated as the first fault when it may be the result of another engine issue preventing clean regeneration.

How to use this page

This page explains the code in plain English and gives indicative UK repair and MOT context. It does not confirm the exact failed part. Vehicle age, engine, related codes, live data, and workshop inspection can all change the final diagnosis and quote.

What does fault code P2002 mean?

P2002: DPF not clearing soot efficiently, often from short journeys. Try a proper regen drive before quoting repairs (£100-£1500). When this fault is detected, the ECU (Engine Control Unit) stores the code and usually illuminates the check engine light on the dashboard.

In practice, P2002 should be treated as a diesel aftertreatment and adblue problem first, not as proof that one named part has failed. The value of the code is in narrowing the system, checking related data, and avoiding the usual misdiagnosis before parts are ordered.

Symptoms of fault code P2002

These are the most common symptoms UK drivers report when this code is active:

  • Check engine light on
  • DPF (diesel particulate filter) warning light
  • Loss of power — possible limp mode
  • Excessive black smoke on acceleration
  • Increased fuel consumption

Note that some vehicles show no drivability symptoms at all — the check engine light may be the only sign. This is why scanning the fault code is essential rather than guessing at the cause.

What causes P2002?

These are typical causes to check first:

  1. DPF blocked due to short journeys preventing active regeneration
  2. Faulty DPF pressure sensor
  3. EGR fault causing excess soot
  4. Injector fault causing excessive soot loading
  5. Oil contamination of the DPF

It is important to diagnose the root cause before replacing parts. Many unnecessary and expensive repairs happen because the most expensive component is replaced first without proper testing. Always work through the diagnostic steps systematically.

How to fix P2002 — step by step

Work through these steps in order to avoid unnecessary parts replacement:

  1. If the filter is only lightly loaded, a sustained motorway run can sometimes help the car complete regeneration
  2. If the warning returns quickly, a professional forced regeneration or deeper diagnosis may be needed
  3. Check the DPF pressure sensor and related readings if regeneration appears to complete but the fault returns
  4. Consider DPF cleaning or replacement only after soot load, sensor data, and upstream causes have been assessed

After any repair, clear the fault code with an OBD-II scanner and carry out a test drive. If the code returns, continue to the next diagnostic step. For a personalised repair guide specific to your vehicle's make, model, year and engine, use our AI Diagnostic Report below.

UK vehicles commonly affected by P2002

These models are frequently seen with this fault code in UK garages:

  • Volkswagen Golf/Passat (TDI)
  • BMW 3/5 Series (diesel)
  • Ford Focus/Mondeo/Transit (TDCi)
  • Vauxhall Astra/Insignia (CDTi)
  • Peugeot 308/407 (HDi)
  • Renault Megane/Laguna (dCi)

This code can appear on OBD-II compatible vehicles. OBD-II is standard on most UK petrol cars from 2001 and diesel cars from 2004, with many later-1990s vehicles also compatible. The models listed above are examples where owners and garages often encounter this fault, but they are not an exhaustive or ranked list.

DIY difficulty and cost guide

Difficulty: Medium — regeneration drive is DIY. Professional DPF clean costs £100–£300. Replacement is £500–£1500.

UK repair cost estimate: £100–£1500 including parts and labour at average UK workshop rates (inc. VAT). Independent garages are typically 30–50% cheaper than main dealers. Always get at least two quotes.

Prevention: Take regular 30-minute motorway journeys, use quality diesel, service on schedule. DPF cars are not suited to short urban journeys only.

Detailed analysis for P2002

What usually triggers P2002 on UK cars

DPF efficiency faults are heavily influenced by driving pattern in the UK, especially short urban trips that never let regeneration finish. They often sit alongside soot loading, pressure-sensor, EGR, or NOx-related issues.

Checks that save money before replacing parts

  1. Ask about recent driving style before replacing any DPF parts.
  2. Check soot load, differential pressure, and regeneration history.
  3. Look for upstream faults such as EGR, boost, or injector problems that overload the DPF.

Common misdiagnosis to avoid

A blocked DPF is often treated as the first fault when it may be the result of another engine issue preventing clean regeneration.

Questions to ask your garage about P2002

  • What is the soot load and regeneration history?
  • Is the DPF blocked because of another upstream fault?
  • Was a forced regeneration appropriate or is the filter already beyond that stage?

P2002 and the UK MOT test

Fault code P2002 is likely to cause an MOT failure. A stored code does not automatically fail an MOT, but if it keeps the malfunction indicator lamp (MIL / check engine light) on where MIL inspection applies, or affects emissions, it can cause a failure.

Even if the light is not currently on, if the fault is intermittent it could reappear during the test. Use our AI Diagnostic Report to understand the MOT risk specific to your vehicle and get advice on whether it is safe to proceed to your test.

Sources and references

This guide is informed by the following authoritative UK sources:

Repair cost estimates are based on UK labour rates and parts pricing from AA, RAC and independent garage surveys, reviewed quarterly. All content is for educational purposes and is not a substitute for professional mechanical diagnosis.

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Frequently asked questions about P2002

What does P2002 mean in plain English?

P2002 is a diesel aftertreatment and adblue fault code. In practice, P2002 should be treated as a diesel aftertreatment and adblue problem first, not as proof that one named part has failed. The code helps narrow the system, check related data, and avoid misdiagnosis before parts are ordered.

Will P2002 fail an MOT?

P2002 is likely to affect MOT outcome if the fault is active, keeps the warning light on, or causes emissions failure.

Can I keep driving with P2002?

Try a DPF regeneration run (30 min motorway at 60mph+) first. If the light stays on, get it diagnosed.

How much does it usually cost to fix P2002 in the UK?

Typical UK repair costs for P2002 range from £100–£1500, depending on the underlying fault, your exact vehicle, and local labour rates.

Related guides for P2002

Use these supporting pages to compare likely repair paths, warning-light behaviour, MOT risk, and the questions to ask before approving work.

DPF fault codes guide UKWill an engine management light fail MOT?

Related and nearby OBD2 codes

Compare P2002 with closely related faults, nearby codes in the same family, and adjacent module or sensor faults that often need to be ruled out during diagnosis.

P2003
Diesel Particulate Filter Restriction Ash Acc…
P2459
Diesel Particulate Filter Regeneration Freque…
P0401
EGR Flow Insufficient — Carbon Buildup or Val…
P0420
Cat Efficiency Below Threshold — Check O2 Sen…
P0171
System Too Lean — Vacuum Leak or Fuel Deliver…
P1610
NATS Malfunction Immobiliser Fault
P0755
Shift Solenoid B Malfunction
P2200
NOx Sensor Circuit Bank 1
P20E8
Reductant Injection Performance
P203F
Reductant Level Sensor Performance
P0A0F
Drive Motor A Performance
P0A09
DC/DC Converter Status Circuit Low

Last updated: August 2026. AI-Diagnostics-Pro provides AI-generated information for educational purposes only. It is not a substitute for professional automotive advice. Always consult a qualified mechanic before carrying out vehicle repairs. Repair cost estimates are approximate and may vary by region and vehicle.