Used car guide

2004 Vauxhall Signum diesel: common problems and MOT failures

What MOT testers find on the diesel Vauxhall Signum first registered in 2004 (diesel cars only): we looked at the 205 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

Small sample: there were only 205 MOTs of these cars during 2023–2025, so treat the percentages as rough. The known faults below don't depend on it.

205MOTs of 2004 diesel cars, done in 2023–2025
53%pass first time (all 2004 cars: 57%)
6,800typical miles a year
2.4×the usual rate for number plate lights

What goes wrong more than usual on a 2004 Vauxhall Signum diesel?

Parts flagged at MOT more often on the 2004 Vauxhall Signum diesel than on all cars registered in 2004.

  • Number plate lights2.4× usual
    Vauxhall Signum
    18.5% All 2004 cars
    7.8%

    Failed outright at MOT: 3.4%, against 2.3% of all 2004 cars. The rest were advisories or minor defects.

    Rough price £5–£40 our estimate

    At the viewing: Check the number plate lights work and the plates are clean and legal.

  • Drive shaft (CV) joints2.5× usual
    Vauxhall Signum
    16.6% All 2004 cars
    6.6%

    Failed outright at MOT: 9.8%, against 3% of all 2004 cars. The rest were advisories or minor defects.

    Rough price £60–£350 our estimate

    At the viewing: Drive slowly on full steering lock in both directions and listen for clicking. Look for split rubber boots behind the front wheels.

Common 2004 Vauxhall Signum diesel MOT failures and advisories

The share of 2004 Vauxhall Signum diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    57% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

  • Brakes
    52% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Lights and electrics
    41% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Tyres
    35% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Oil and fluid leaks
    21% of testsRough price £80–£600

    At the viewing: Look under the engine and on the ground where the car is usually parked for fresh oil or fluid.

  • Driveshafts and joints
    18% of testsRough price £60–£350

    At the viewing: On full steering lock, drive slowly and listen for clicking from the front wheels.

Questions to ask the seller before buying a 2004 Vauxhall Signum diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

  1. Any recent work on the number plate lights? (Flagged at MOT 2.4× as often on the 2004 Vauxhall Signum diesel as on other cars the same age.)
  2. Any recent work on the drive shaft (cv) joints? (Flagged at MOT 2.5× as often on the 2004 Vauxhall Signum diesel as on other cars the same age.)
  3. Can I see the service history and receipts for any big jobs?

Looking at a Vauxhall Signum?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

Every year of the Vauxhall Signum compared

YearMOT testsMost flagged
2008–Too few tests
2007880Brakes 46%
20061,364Suspension 48%
2005700Suspension 49%
2003143Brakes 57%

Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of Vauxhall Signum cars first registered in 2004. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score