Vauxhall Signum MOT Failures
An analysis of 16,069 real DVSA MOT tests on the Vauxhall Signum — what fails, how often, and how that compares to every other car on UK roads. Generations covered: Gen1 (2003–2008).
Where the Vauxhall Signum fails its MOT
The single biggest MOT failure point on the Vauxhall Signum is exhaust system damage — this model is 18 times more likely to fail on this item than the average car on UK roads. That makes it a significant weak point for anyone buying or owning this model. Across 16,069 MOT tests, 16.45% of all Vauxhall Signum tests recorded this as a failure.
Bodywork failures usually mean structural corrosion — not cosmetic rust, but rot that affects the car's structural integrity. Check sills, subframes, and chassis rails carefully, especially on older examples.
Other notable weak points include headlight fault (9.9x the fleet average), emissions failure (21x the fleet average), brake hoses perished or damaged (9.0x the fleet average), and suspension component damaged or corroded (9.4x the fleet average). These ratios compare the Vauxhall Signum's failure rate on each item against the national average for all cars tested — a ratio of 10x means this model fails ten times more often than a typical car.
The failures span 5 categories: Bodywork, Lights & Electrics, Exhaust & Emissions, Brakes, Suspension. If you're inspecting a Vauxhall Signum before purchase, these are the areas to focus on — and if any have been flagged as advisories on a previous MOT, they're likely to become failures in the near future.
How failures change with mileage
The Vauxhall Signum's weak points shift as the car covers more miles. Understanding these patterns helps you know what to expect — and what to budget for — at each stage of ownership.
Under 60,000 miles
At this mileage, most failures are either design-related or caused by age rather than wear. Components like bushes and drop links may not have been replaced yet, and original-fit parts can deteriorate even on low-mileage cars that spend a lot of time sitting.
For the Vauxhall Signum specifically, the DVSA data shows the most common failures at this mileage are exhaust system damage (18x the average) and brake pipes corroded (7.2x). coil springs broken (5.8x) and fluid leak (5.3x) also appear frequently.
60,000 to 100,000 miles
This is where routine wear items start to show up. Brake components, tyres, and exhaust parts have done serious work by this point. Cars that have been well serviced will show fewer of these failures — this mileage band is where good maintenance really separates the well-kept from the neglected.
For the Vauxhall Signum specifically, the DVSA data shows the most common failures at this mileage are emissions failure (21x the average) and exhaust system damage (9.4x). brake hoses perished or damaged (9.0x) and headlight fault (9.0x) also appear frequently.
Over 100,000 miles
High-mileage cars accumulate failures across multiple systems. The key question isn't whether things will need doing — they will — but whether the car has been maintained well enough to keep on top of them. Look for a consistent service history and recent MOT passes with minimal advisories.
For the Vauxhall Signum specifically, the DVSA data shows the most common failures at this mileage are emissions failure (17x the average) and anti-roll bar links worn (6.7x). brake hoses perished or damaged (6.3x) and exhaust system damage (6.1x) also appear frequently.
The shift from exhaust system damage at lower mileages to emissions failure at higher mileages is typical — early failures tend to be design or factory-related, while high-mileage failures reflect accumulated mechanical wear. A car that's been well maintained will usually dodge the worst of both.
Known issues beyond the MOT
An MOT only tests roadworthiness at a single point in time — it won't catch developing faults, intermittent problems, or issues that haven't yet reached the failure threshold. These are the issues that Vauxhall Signum specialists and owners flag most frequently, drawn from manufacturer technical bulletins, workshop data, and verified owner reports.
Brake hose ferrule corrosion Major
The brake hose ferrules (metal crimped connectors where flexible brake hoses connect to hard brake lines) suffer from accelerated corrosion on the Signum. Affects Gen1; typical independent garage repair cost is £150–£300.
Brake pipe corrosion Major
The steel brake pipes on the Signum suffer from accelerated corrosion, particularly where they run along the underbody and around the rear axle area. Affects Gen1; typical independent garage repair cost is £200–£400.
Suspension component corrosion and damage Major
Suspension components on the Signum suffer from excessive corrosion and structural damage, particularly affecting the 1.9-litre diesel variant. Affects Gen1; typical independent garage repair cost is £300–£800.
Exhaust system corrosion and mounting failure
The exhaust system on the Signum suffers from accelerated corrosion and mounting point failure. Affects Gen1; typical independent garage repair cost is £200–£500.
For the complete picture — including repair costs across independent, specialist, and dealer garages — see the full Vauxhall Signum common problems breakdown.
What to check before buying a Vauxhall Signum
Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Vauxhall Signum:
Bodywork — check for exhaust system damage. Lights & Electrics — check for headlight fault. Exhaust & Emissions — check for emissions failure. Brakes — check for brake hoses perished or damaged, brake pipes corroded.
Beyond the MOT items, ask specifically about brake hose ferrule corrosion and brake pipe corrosion. These won't show up on a standard MOT but can be expensive to fix — repairs start from £150. A specialist pre-purchase inspection is worth the investment on this model.
Always check the car's full MOT history for patterns — recurring advisories often become failures within 12 months. And verify the service history to confirm maintenance has been kept up to schedule. Enter any reg into our free car check to see the complete picture.
Looking at a specific Vauxhall Signum?
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Vauxhall Signum MOT FAQs
What are the most common MOT failures on a Vauxhall Signum?
Based on 16,069 DVSA MOT tests, the most common failure is exhaust system damage — at 18x the national fleet average. Other frequent failures include headlight fault and emissions failure.
Is the Vauxhall Signum reliable based on MOT data?
The Vauxhall Signum has 11 MOT failure categories above the fleet average. Specialists also flag brake hose ferrule corrosion as a concern. A pre-purchase inspection and service history check are recommended.
What MOT failures should I expect at high mileage?
Above 100,000 miles, the Vauxhall Signum most commonly fails on emissions failure and anti-roll bar links worn. Under 60,000 miles, the main issues are exhaust system damage and brake pipes corroded.
How do I check a Vauxhall Signum's MOT history?
Enter the registration number into our free car check above. You'll see every MOT test result, advisories and failures, mileage readings, write-off status, and finance checks.
MOT failure data sourced from DVSA bulk test records via data.gov.uk. Ratios compare this model's failure rate against the national fleet average. Known issues sourced from manufacturer bulletins, specialist workshops, and verified owner reports.