MOT fail · manual section 6.1.1
Sub-frame has excessive corrosion which adversely affects braking or steering
What this MOT fail means, how often testers record it and what garages charge per hour. From 130,233,413 DVSA MOT tests taken 2022 to 2025.
MOT data updated
Times recorded adds every DVSA code with this wording, so a test can record it more than once, for example on two wheels under separate codes.
What it means
This is a dangerous defect: the car fails its MOT. A dangerous defect is a direct and immediate risk to road safety or the environment. The car fails its MOT and should not be driven until it is repaired.
The tester looks at the body and underside for corrosion and damage, especially near the points where suspension, steering and seat belts are mounted, and checks the exhaust, fuel system, drive shafts and towbar.
The MOT inspection manual describes the defect (section 6.1.1) as:
Vehicle structure corroded to the extent that steering or braking is likely to be adversely affected
Read this section of the MOT inspection manual on GOV.UK
| Result | Manual item | DVSA defect text | Records |
|---|---|---|---|
| Fail Dangerous | Sub-frame condition | has excessive corrosion which adversely affects braking or steering (6.1.1) | 2,239 |
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How common it is by age
Testers record it most at 15 years: 0.006 per 100 MOTs (n=5,591,675 tests at that age).
| Age | Fail per 100 | Tests (n) |
|---|---|---|
| 9 years | 0 | 9,949,012 |
| 10 years | 0.001 | 9,049,507 |
| 11 years | 0.002 | 8,087,514 |
| 12 years | 0.003 | 7,303,151 |
| 13 years | 0.004 | 6,612,160 |
| 14 years | 0.005 | 6,054,526 |
| 15 years | 0.006 | 5,591,675 |
| 16 years | 0.005 | 4,858,625 |
| 17 years | 0.005 | 4,040,458 |
| 18 years | 0.005 | 3,261,622 |
| 19 years | 0.006 | 2,479,858 |
| 20 years | 0.004 | 1,845,952 |
| 21 years | 0.004 | 1,321,417 |
| 22 years | 0.004 | 913,980 |
| 23 years | 0.005 | 619,531 |
Repair and cost
We do not map this defect to one repair job, because the fix depends on the cause. Garages charge by the hour, so ask for a quote that lists labour time and parts.
Median hourly rate charged for car repairs, from 1,058 local garage and 953 main dealer price quotes collected by the ONS, September 2025 to August 2026. The same shops are priced each month, so the number of shops is the real sample.
Related MOT defects
- Exhaust system has a minor leak of exhaust gases1.92 per 100
- Drive shaft constant velocity boot severely deteriorated1.40 per 100
- Drive shaft constant velocity boot split or insecure, no longer prevents the ingress of dirt1.35 per 100
- Exhaust system mounting defective0.82 per 100
- Exhaust system has a major leak of exhaust gases0.75 per 100
- Chassis condition is corroded but structural rigidity is not significantly reduced0.38 per 100
- Integral vehicle structure condition is corroded but structural rigidity is not significantly reduced0.37 per 100
- Exhaust system insecure0.28 per 100
- Integral vehicle structure condition corroded to the extent that the rigidity of the assembly is significantly reduced0.13 per 100
- Door condition cannot be opened from outside the vehicle0.13 per 100
All body, structure and attachments defects All MOT defects Car repair costs
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Source
Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025, and the MOT inspection manual published on GOV.UK. Prices: ONS consumer price inflation price quotes, September 2025 to August 2026, UK.
MOT data updated . Prices updated .
Not affiliated with or endorsed by DVSA or the Office for National Statistics. How we calculate these figures · Data sources