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Diagnostic tool

Is it really the filter?
Eight questions will tell you.

A transparent scoring model over the symptoms we see most often. It weighs your answers across eight possible causes and shows you exactly which answers drove the result, including the cases where the filter is fine and something upstream is at fault.

Questions
8
Possible causes
8
Time needed
~60 seconds
Cost
Free

Question 1 of 8

What is the vehicle telling you right now?

Why we show our working

Plenty of workshops will tell you the filter is blocked because that is the expensive answer. This tool scores your answers against eight causes and names the ones that pointed where it landed, so you can judge the reasoning rather than take it on trust.

Two of the eight outcomes conclude you probably do not need us yet. We would rather tell you that.

Before you answer

  • Have the odometer reading or engine hours to hand.
  • Think about the last month of use, not just today.
  • If a garage has already given you a fault code, keep it: it is worth more than any online tool.
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What it can find

Eight causes, not one

A blocked-filter warning has more than one explanation, and several of them are considerably cheaper to fix than a clean.

soon

Ash-loaded filter: cleaning required

Your answers point to accumulated ash rather than soot. Regeneration cannot remove ash; the filter needs physical cleaning.

₹6,500 – ₹24,000

soon

Soot-loaded filter: regeneration candidate

The pattern suggests combustible soot build-up. A supervised regeneration may clear it without removing the filter.

₹2,500 – ₹3,500

routine

Possible sensor fault: filter may be fine

Your symptoms are consistent with a faulty sensor reporting a blockage that may not exist.

₹1,800 – ₹2,800

urgent

Likely injector problem loading the filter

Rapid reloading and smoke point upstream: an injector is probably putting unburnt fuel into the exhaust.

₹3,200 +

urgent

Turbocharger condition affecting the filter

Blue smoke, oil consumption or boost problems suggest the turbo is contributing to filter loading.

₹2,600 +

soon

Possible EGR system fault

The symptom pattern is consistent with excessive exhaust gas recirculation raising soot output.

₹1,500 +

routine

Driving pattern preventing regeneration

The filter may be recoverable through a change in use, without workshop intervention.

₹1,500

urgent

Possible substrate damage: assessment needed

Some answers raise the possibility of physical damage to the filter core. This needs inspection before anything else.

Assessment ₹1,500

Before you trust the result

The basics behind the questions

What the filter is, why it blocks and what the warning signs mean. The scoring above assumes these; the full set of answers is on the FAQ page.

All questions answered

A Diesel Particulate Filter is a honeycomb ceramic substrate fitted in the exhaust system that traps soot particles before they leave the tailpipe. It is mandatory on BS-IV and BS-VI vehicles in India. The filter is designed to periodically burn off trapped soot in a process called regeneration, but it cannot burn off ash, which accumulates permanently over the filter's life and eventually requires physical cleaning.

Cleaning is a physical process applied to a ceramic substrate, so what governs whether it works is the filter's size and condition rather than the badge on the bonnet. We routinely see cars and SUVs, pickups, light and heavy commercial vehicles, buses, construction plant, agricultural machinery, gensets and marine diesels, and the supported vehicles page lists the manufacturers and models that come in most often. A DPF is mandatory on BS-IV and BS-VI vehicles in India, and both platforms are cleaned the same way, as are off-highway Tier III, Tier IV and CEV BS-IV filters. If your vehicle is not listed, the compatibility checker will tell you whether its filter can be cleaned rather than replaced, or send us the details for a straight answer.

Two different things accumulate. Soot is combustible and is removed by regeneration. Ash, from engine oil additives and normal wear, is not combustible and builds up permanently. A filter blocks when either regeneration stops working (so soot accumulates faster than it clears) or when ash has simply filled the substrate over years of service. Short urban trips, excessive idling, faulty injectors, a failing turbocharger, EGR problems and low-quality fuel all accelerate the process.

Regeneration needs sustained high exhaust temperature, which typically means extended running at speed. The most common causes of failure are short journeys that never reach temperature, repeatedly interrupted cycles from switching the engine off mid-regeneration, a faulty differential pressure or exhaust temperature sensor reporting incorrect values, injector problems, EGR faults, low fuel level (many vehicles inhibit regeneration below a quarter tank) and an already ash-saturated filter that has passed the point where regeneration can help.

The DPF warning light is the obvious one, but it usually appears late. Earlier signs include noticeable loss of power or a limp-mode derate, increased fuel consumption, a cooling fan running more than usual, frequent or continuous regeneration attempts, a strong hot or acrid smell after driving, difficulty starting, and visible smoke from the exhaust. If you are seeing several of these together, the filter needs assessment before it reaches the point where regeneration can no longer help.

No. Removing or disabling a diesel particulate filter on a road-going vehicle is illegal under the Central Motor Vehicles Rules, will fail a Pollution Under Control test, and invalidates your insurance and manufacturer warranty. We do not offer DPF deletion or ECU remapping to bypass emission systems under any circumstances. Cleaning restores the filter to working condition and keeps the vehicle fully compliant, which is both the legal answer and, in almost every case, the cheaper one.

After the check

Confirm it with a measurement

Whatever the tool suggested, a 60–90 minute diagnostic settles it with ECU data and a real back pressure reading, and the cost is credited against whatever work follows.