Model Reports 4 min read Updated 18 Oct 2026

Mazda 3 2004: reliability & common MOT faults

In 2025, 52 in every 100 first MOTs on a 2004 Mazda 3 were passes. Most common reason for a fail: Petrol engine warning light.

Summary

With 527 first tests, there are too few to say whether the 2004 Mazda 3 differs from the model years either side. Treat the faults below as a checklist.

At a glance

How 527 first tests went in 2025.

Passed first time
52 in every 100
Did not pass first time
48 in every 100255 failed first-attempt tests
The typical car
21 yearsabout 95,339 miles
First tests counted
527

What failed most often

  1. Petrol engine warning light20 in every 100 failed tests

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2004 Mazda 3 vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Noise, emissions and leaks

One fault: petrol engine warning light, 2.9 times as often as on similar cars.

Figures below are measured across the 255 failed first attempts in 2025 that had a mileage recorded, which allows a like-for-like comparison.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Petrol engine warning light

Failed on 51 first tests2.9 times as often as similar carsPossible evidence

What it means

The malfunction indicator lamp (MIL) on a petrol engine is a Major failure when it is illuminated indicating a malfunction. The detail line DVSA gives for the same row also names an inoperative lamp. The test covers only certain petrol vehicles, depending on their age, size and fuel type.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Seat belts and restraints

One fault: airbag warning light, 2.7 times as often as on similar cars.

Airbag warning light

Failed on 22 first tests2.7 times as often as similar carsPossible evidence

What it means

The airbag warning lamp (SRS MIL in DVSA's wording) is failed only if it indicates a system malfunction, which is Major. A lamp lit to show the passenger airbag is disabled is not to be regarded as a defect. Dashboard messages are not a defect in their own right, though they can help the tester confirm a malfunction.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Suspension

Two faults. The strongest is the suspension arm pins and bushes (front): 2.2 times as often as on similar cars.

Suspension arm pins and bushes (front)

Failed on 22 first tests2.2 times as often as similar carsPossible evidence

What it means

Pins and bushes on suspension arms fail as Major when they are excessively worn. They are graded Dangerous when likely to become detached. DVSA uses the same wording for a suspension joint.

Suspension mounting area (rear)

Failed on 31 first tests2.2 times as often as similar carsPossible evidence

What it means

The load bearing structure within a set distance of a sub-frame, spring or suspension component mounting is a prescribed area. Major applies when its strength or continuity is significantly reduced or it is inadequately repaired. Dangerous applies when it is so weakened that control of the vehicle is likely to be adversely affected.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 22 first tests, 2.1 times as often as on similar cars.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

Advisories

Other things testers noted as worn or close to failing, more often than on similar cars.

An advisory is a note from the tester about something that has not failed yet. It is an early warning, not a fail. Advisories for the faults above are shown with those faults.

Suspension arm (rear)

Noted on 33 first tests4.9 times as often as similar carsElevated evidence

Suspension sub-frame (rear)

Noted on 67 first tests4.6 times as often as similar carsElevated evidence

Suspension sub-frame (front)

Noted on 23 first tests3.3 times as often as similar carsElevated evidence

Data: UK MOT open data, 2025. Counts cover advisories recorded on failed first tests only, compared with cars of the same age and mileage.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time
52in every 100
Passed on the first test.
Fixed at the station
8in every 100
Failed, then fixed at the test station the same day.
Failed
40in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 51.6% of 527 first tests (2025): only cars that passed first time count. Official-style pass 60.3%: cars fixed at the test station also count as a pass. The 8 fixed and the 40 not fixed make the 48 in every 100 that did not pass first time.

Same model, other years

Passed first time in every 100, all tested in 2025.

4060801002004201020152020
406080100200420102020

Newer cars are younger, so look for a jump rather than the climb. A year earlier (2024), when these cars were a year younger, 46 in every 100 passed first time.

YearPassed first timeFirst tests
2004 This car52 in every 100527
200547 in every 1001,851
200650 in every 1002,787
200751 in every 1004,012
200850 in every 1005,080
200956 in every 1006,367
201057 in every 1007,309
201156 in every 1004,922
201263 in every 1004,536
201368 in every 1004,879
201470 in every 1007,914
201570 in every 10011,187
201673 in every 10010,120
201774 in every 1007,934
201883 in every 1006,846
201987 in every 1004,329
202087 in every 1004,157
202189 in every 1003,964
202292 in every 1002,415

FAQs

Short answers about how to read this model-year guide.

With 527 first tests, there are too few to say whether the 2004 Mazda 3 differs from the model years either side. Treat the faults below as a checklist. In 2025, 51.6% of 527 first MOTs on the 2004 Mazda 3 passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 60.3%. Among 255 failed first-attempt MOT tests (test year 2025), Petrol engine warning light appears more often than on similar cars (20.0% of those tests; 51 observed failures; about 2.9× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.
Ranked by how often they were actually recorded, the items that most often failed a 2004 Mazda 3 at the first attempt were Petrol engine warning light (20.0%), each as a share of the year's failed first attempts. That is what goes wrong most often on the car. The common faults table shows a different measure: faults that are unusual compared with similar cars.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Petrol engine warning light (20.0% of those tests; 51 observed failures; about 2.9× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Petrol engine warning light shows up more often than on similar cars (20.0% of those tests; 51 observed failures; about 2.9× more often than similar cars). That does not prove a design fault. Age, mileage, and how the car was used still matter. Treat it as a pre-purchase checkpoint, not a manufacturer service bulletin.
Common MOT problem areas for the 2004 Mazda 3 include Petrol engine warning light, Airbag warning light, Suspension arm pins and bushes (front). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.
Advisories flag issues noted at the test and are not a fail rate. We show advisory patterns that appear more often than on similar cars among failed first-attempt tests, separate from common failure rows. Use them as early-warning checks, not as a pass/fail score.
This page highlights MOT failure patterns for the 2004 Mazda 3 (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics, not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars, not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics; this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces, but does not remove, differences in how cars were used and maintained.
  • If the data for a car is too thin to say anything useful, we say so rather than guess.

Contains public sector information licensed under the Open Government Licence v3.0.

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