At a Glance
The Mazda B-series 5th gen UN has 46 identified problems that occur more often than the UK average, with Brake hydraulic component worn being the most reported. Electrical is the most common MOT failure category. The most serious issue flagged is Brake performance below minimum, rated as dangerous. Based on 86K MOT tests from DVSA data.
Problems are patterns in the DVSA data that occur significantly more often on this model than the UK average — confirmed at 99% statistical confidence. Read how we calculate MOT pass rates and problems →
Below: the full MOT-data picture for the Mazda B-series 5th gen UN — MOT pass rate vs the UK average, common problems vs UK fleet patterns, the most likely MOT failures by frequency, fault occurrence by mileage band, and pass/fail trends. All numbers drawn from DVSA records.
Mazda B-series 5th gen UN MOT Pass Rate
Across 86K MOT tests from DVSA data, the Mazda B-series 5th gen UN (1998–2006) has a fail rate of 42.5%.
UK average fail rate (2006): 35.3%
Common Mazda B-series 5th gen UN Problems
Owner-submitted reports plus patterns we've identified across 559 million UK MOT tests. Each MOT-derived item below — whether tagged as a Problem, Wear & Tear or Consumable — shows up noticeably more often on this generation than across the UK fleet, which is why it's here. Owner reports are pinned to the top by default; use the sort and filter pills below to view a specific tier or change the order.
Brake hydraulic component worn
8,735
occurrences
Fog lamp not working
7,257
occurrences
Driveshaft fault
5,639
occurrences
Wiper blades deteriorated
5,053
occurrences
Exhaust system fault
4,119
occurrences
Tell Us About Your Problem
Help other Mazda B-series 5th gen UN owners — report a problem and we'll add it to the database
Tell Us About Your Problem
Help other Mazda B-series 5th gen UN owners — report a problem and we'll add it to the database
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Problems by mileage
Common problems, MOT failures and advisories on the Mazda B-series 5th gen UN, grouped by the mileage they typically appear at.
444 distinct problems · 205,303 total occurrences in current filter
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Advisory items are MOT tester observations. Frequency can be influenced by driving style and usage patterns.
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Other Mazda B-series Generations
4th gen UF
1985–1998
7 problems
5th gen UN
1998–2006
61 problems
Current page
Frequently Asked Questions
What are the most common Mazda B-series 5th gen UN problems?
Based on DVSA MOT data for the Mazda B-series 5th gen UN (1998–2006), we have identified 46 common problems. The most frequently reported is "Brake hydraulic component worn". Electrical is the most common MOT failure category.
How reliable is the Mazda B-series 5th gen UN?
This generation has 86K MOT tests on record with a 42.5% fail rate. A fault is flagged as a "Common Problem" only when it occurs significantly more often on this model than the UK average, confirmed at 99% statistical confidence.
What commonly fails the MOT on a Mazda B-series 5th gen UN?
There are 178 distinct MOT failure types recorded for the 5th gen UN (1998–2006), grouped by the mileage these failures typically occur. See the Common MOT Failures section on this page.
Can I report a problem with my Mazda B-series 5th gen UN?
Yes — use the "Tell Us About Your Problem" form on this page. Your report helps other Mazda B-series owners spot problems early. All submissions are reviewed before being added to the public database.
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