MajorCommonEngine

Honda Accord: N22A1 Diesel Particulate Filter Premature Blockage

N22A1 Diesel Particulate Filter Premature Blockage is a common engine fault on the Honda Accord on the 2004–2008 cars, and we rate it major. Putting it right costs $300 to $3,200 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 55 documented faults on the Honda Accord.

Vehicle: Honda Accord
Years: 2004–2008
Fuel: diesel
System: Engine

This page covers the Honda Accord as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Honda Accord faults55 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Diesel particulate filter yet. We would rather show none than show a picture of a different part.

What goes wrong

Later N22A1-equipped Accords fitted with a diesel particulate filter (DPF) suffer premature blockage when the vehicle is regularly driven on short urban trips below the exhaust temperature needed for passive regeneration (approximately 550°C). Forced active regeneration fails to complete if trips are consistently short, leading to soot accumulation that eventually triggers a non-recoverable warning and requires either professional forced regeneration or DPF replacement. DPF units are expensive and genuine Honda units have limited NZ/AU availability.

What you would notice

DPF warning light illuminated on instrument cluster
Noticeable reduction in fuel economy as the ECU attempts active regeneration
Engine running roughly during regeneration cycles with increased idle speed
Strong sulphurous or burning smell from exhaust during failed regeneration
Complete power limitation when DPF soot load reaches critical threshold

How to check it

Where to look. Exhaust system, DPF canister located under the vehicle mid-section behind the catalytic converter

Look for DPF warning lamp on the dash (distinct from engine MIL).
Check exhaust for excessive soot and ask owner about typical driving patterns.
Inspect for evidence of DPF cleaning or replacement invoices.
If a workshop inspection is possible: Connect an OBD-II scanner with live data and check DPF soot load percentage if supported.

Parts involved: Diesel particulate filter.

What it costs to put right

$300 to $3,200 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the DPF ever been cleaned, regenerated professionally, or replaced?”
“Is the vehicle used mainly for short trips under 20 km or longer highway runs?”
“Has the DPF warning light ever come on, and was it resolved?”

Now check the Honda Accord you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Honda Accord buyer questions

Is n22a1 diesel particulate filter premature blockage serious on a Honda Accord?

We rate it major and common on the Honda Accord. Later N22A1-equipped Accords fitted with a diesel particulate filter (DPF) suffer premature blockage when the vehicle is regularly driven on short urban trips below the exhaust temperature needed for passive regeneration (approximately 550°C). Forced active regeneration fails to complete if trips are consistently short, leading to soot accumulation that eventually triggers a non-recoverable warning and requires either professional forced regeneration or DPF replacement. DPF units are expensive and genuine Honda units have limited NZ/AU availability.

How much does it cost to fix on a Honda Accord?

$300 to $3,200 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Honda Accord years are affected?

Our research records this fault on the 2004–2008 Honda Accord. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Look for DPF warning lamp on the dash (distinct from engine MIL). Check exhaust for excessive soot and ask owner about typical driving patterns. Inspect for evidence of DPF cleaning or replacement invoices. If a workshop inspection is possible: Connect an OBD-II scanner with live data and check DPF soot load percentage if supported. Look here: Exhaust system, DPF canister located under the vehicle mid-section behind the catalytic converter