Know Your MOT

MOT failure rate and common problems for the Mercedes O814, and how to check your own car by registration.

Updated 05 September 2026.

30.2%fail rate

Mercedes O814 MOT failure rate

What a Mercedes O814 fails its MOT on, and the part that fixes each.

What it fails on, and why

Lamps & electrical5.3% 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.

Seat belts5.3% of failures

Seat-belt failures are frays, cuts, corroded anchorages, or a belt that will not lock under a sharp pull or retract properly.

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: Mercedes O814 headlight and indicator bulbsShop Mercedes O814 headlight and indicator bulbs on AmazonaffiliateFind Mercedes O814 headlight and indicator bulbs on eBayaffiliate
For the seat belts failure: Mercedes O814 seat beltsShop Mercedes O814 seat belts on AmazonaffiliateFind Mercedes O814 seat belts on eBayaffiliate

Other models

All Mercedes models MOT failure rates comparedRanked worst to bestMercedes C220 MOT failures28.8% failure rateMercedes Ml MOT failures21.9% failure rateFord Fiesta MOT failures27.1% failure rate

Questions and answers

What is the MOT failure rate of the Mercedes O814?

It fails 30.2% of its MOT tests across the DVSA record, from 63 tests.

What do these cars fail their MOT on most?

The most common failure area is lamps & electrical, at 5.3% of this model's failures.