Know Your MOT

MOT failure rate and common problems for the Reliant Tw9, and how to check your own car by registration.

Updated 05 September 2026.

14.5%fail rate

Reliant Tw9 MOT failure rate

What a Reliant Tw9 fails its MOT on, and the part that fixes each.

What it fails on, and why

Lamps & electrical37.5% of failures

Lighting is the single most common MOT failure and the cheapest to put right. A blown headlight, brake-light or number-plate bulb, a cracked lens, or a headlamp beam that points too high or low will all fail. Most are a two-minute bulb swap.

Brakes37.5% of failures

Brake failures cover worn pads and discs, an imbalance between wheels, corroded or scored discs, or a binding caliper. Braking efficiency is measured on a rolling road, so a spongy or pulling brake shows up as a low reading.

Other12.5% of failures

This covers a range of smaller items, from a non-working horn to a warning light left on.

Visibility/wipers12.5% of failures

Visibility failures include torn or smearing wiper blades, a washer jet that does not reach the screen, and chips or cracks in the driver's swept area. Blades and washer fluid are quick, cheap fixes.

Fuel system12.5% of failures

Fuel-system failures are leaks or an insecure filler cap.

The parts that fix each

If your car has just failed, you have 10 working days to fix the items and get a free partial retest. Confirm the exact fitment against your registration or VIN before buying.

For the lamps & electrical failure: Reliant Tw9 headlight and indicator bulbsShop Reliant Tw9 headlight and indicator bulbs on AmazonaffiliateFind Reliant Tw9 headlight and indicator bulbs on eBayaffiliate
For the brakes failure: Reliant Tw9 brake pads and discsShop Reliant Tw9 brake pads and discs on AmazonaffiliateFind Reliant Tw9 brake pads and discs on eBayaffiliate
For the visibility/wipers failure: Reliant Tw9 wiper bladesShop Reliant Tw9 wiper blades on AmazonaffiliateFind Reliant Tw9 wiper blades on eBayaffiliate

Other models

All Reliant models MOT failure rates comparedRanked worst to bestReliant Robin MOT failures28.9% failure rateReliant Rialto MOT failures27.9% failure rateFord Fiesta MOT failures27.1% failure rate

Questions and answers

What is the MOT failure rate of the Reliant Tw9?

It fails 14.5% of its MOT tests across the DVSA record, from 55 tests.

What do these cars fail their MOT on most?

The most common failure area is lamps & electrical, at 37.5% of this model's failures.