# Mercedes-Benz 420 MOT reliability: pass rate and common failures | RegFlags

The Mercedes-Benz 420 passes its MOT first time 80% of the time, from 571 MOT tests. See pass rates by year, common failures and typical mileage.

- First-time MOT pass rate: 80%
- MOT tests analysed: 571 (DVSA anonymised MOT data, 2025)
- Most common failure area: Lights & electrics

## By year of first use and fuel

| Year | Fuel | MOT tests | First-time pass rate |
| --- | --- | --- | --- |
| 2008 | Petrol | 1 (very few mots) | 100% |
| 2007 | Diesel | 4 (very few mots) | 75% |
| 2004 | Petrol | 1 (very few mots) | 100% |
| 1998 | Petrol | 2 (very few mots) | 50% |
| 1997 | Petrol | 1 (very few mots) | 0% |
| 1994 | Petrol | 1 (very few mots) | 0% |
| 1992 | Petrol | 8 (very few mots) | 100% |
| 1991 | Petrol | 11 (very few mots) | 73% |
| 1990 | Petrol | 32 (few mots) | 84% |
| 1989 | Petrol | 121 | 81% |
| 1988 | Petrol | 149 | 81% |
| 1987 | Petrol | 145 | 81% |
| 1986 | Petrol | 88 (few mots) | 75% |
| 1985 | Petrol | 1 (very few mots) | 0% |
| 1982 | Petrol | 1 (very few mots) | 100% |
| 1980 | Petrol | 1 (very few mots) | 100% |
| 1979 | Petrol | 2 (very few mots) | 100% |
| 1974 | Petrol | 1 (very few mots) | 100% |
| 1973 | Petrol | 1 (very few mots) | 100% |

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