MOT failure “Electronic braking system Warning device shows system malfunction” — did it stay fixed?
Last updated · OBDCode UK editorial
Of the 4,043 cars that failed their 2024 MOT on this item, 0.59% (95% CI 0.4–0.9) failed on the same item again in 2025. That is the closest the public data comes to answering whether the defect stayed fixed. That is 51.8 times the <0.1% (95% CI 0.0–0.0) rate among cars that did not fail on this item.
Counts are test records. Compiled by OBDCode UK, edition 2026.1. These are not official statistics and not a DVSA or DVLA statistic. Contains public sector information licensed under the Open Government Licence v3.0.
What this number is
The cohort is every Class 4 vehicle whose first normal 2024 test recorded a failure for “Electronic braking system Warning device shows system malfunction” (electronic braking system). The outcome is that the same vehicle_id failed on the same certificate wording in 2025. Several DVSA reason-for-rejection codes print the same words; those codes are pooled, and a car is counted once.
The control is every other Class 4 vehicle whose first normal 2024 test did not fail on this wording. A car that failed on something else still belongs in the control.
Cars that were not tested in 2025 remain in the 4,043 and count as not repeating. The extracts do not record whether a garage carried out a repair, or why a vehicle never came back. Whether a later 2024 retest passed, among cars that came back for a retest or partial retest, is on this page when that count exists.
These figures are a statistical association from the national MOT extracts. They are not a prediction about this car, and we have not inspected it.
Their rate of failing a 2025 MOT for any reason was 29.9% (95% CI 28.5–31.3), against 21.6% (95% CI 21.6–21.6) for cars that did not fail on this item.
The same 4,043 cars were 10.5 percentage points more likely not to be tested again in 2025 (19.1% (95% CI 18.0–20.4) versus 8.7% (95% CI 8.7–8.7) for cars that did not fail on this item). The extracts do not record scrappage; a missing later test is the public signal that the vehicle was not presented.
The median car in this cohort was 12.0 years old with 93,112 miles at the 2024 test.
Odometer change to the next annual MOT
Among cars with a valid pair, the median odometer change from the 2024 MOT that recorded the failure to the next annual MOT. n is the count of those pairs; it is not the fail cohort. A later passed retest does not stop this interval.
Scroll horizontally to read every mileage percentile.
| 2024 index test | Cars with a valid pair | 10th pct | 25th pct | Median | 75th pct | 90th pct |
|---|---|---|---|---|---|---|
| Failed on this line | 3,211 | 1,340 | 3,301 | 6,052 | 9,576 | 13,996 |
| Did not fail on this line | 28,527,662 | 1,503 | 3,153 | 5,744 | 9,188 | 13,365 |
The median on this line is 308 miles above the control median.
Of the 3,173 cars that failed on this line and then passed a later 2024 retest, half did so within 2 days. That planning figure excludes same-day station rectification.
A same-day pass with rectification at the station is work done on that visit, not a garage trip. A day count of 0 on that outcome is the same calendar day as the failed test. Including those same-day station passes, half of the passed retests sat at 2 days. Same-day station rectification was 0% (95% CI 0.0–0.1) of the passed retests.
A quarter of those passed retests sat within 0 days; three-quarters within 6 days.
Among the 3,183 cars that came back for a later 2024 retest, 99.7% (95% CI 99.4–99.8) passed on the first completed attempt. A first-attempt fail and a later pass is a come-back and a passed retest, and is not a first-time pass.
These day figures are published only when at least 300 cars passed a later 2024 retest. The later test is a retest or a partial retest at the station. A later annual test is not this interval. A fail late in 2024 that first passed a retest in 2025 is outside this window. This block is the calendar days from the failed test to the first later retest that passed, among cars that have that later pass in 2024 — not a prediction about this car, and not half of the fail cohort. The observation is a passed retest.
Same wording across later years
Of 3,987 cars that failed this wording on their earliest 2023 annual test, 0.48% (95% CI 0.3–0.7) also failed on the same wording in 2024, and 0% (95% CI 0.0–0.1) failed on it in 2023, 2024 and 2025. This is consecutive years of the same certificate line, not a garage outcome. Cars that skip 2024 are not in the three-year count (8 failed on it in 2023 and 2025 but not 2024).
Still tested two years later
Of 3,987 cars that failed this wording on their earliest 2023 annual test, 70.4% (95% CI 68.9–71.8) appear in the 2025 Class 4 extract at all (29.6% (95% CI 28.2–31.1) do not). A missing later test is not scrappage. This is not the one-year not-tested gap already on this page.
By fuel at the 2024 test
Petrol and diesel are different faults. Each row is that fuel only. It is not the all-fuels same-item rate already on this page. The not-tested gap is percentage points versus other cars of the same fuel that did not fail on this wording.
Scroll horizontally to read every fuel column.
| Fuel | Cars | Same-item fail | Not-tested gap |
|---|---|---|---|
| Petrol | 1,474 | 0.47% (95% CI 0.2–1.0) | +11.9 pp |
| Diesel | 2,426 | 0.66% (95% CI 0.4–1.1) | +9.2 pp |
By age at the 2024 test
Scroll horizontally to read every age column.
| Age | Cars | Same-item fail | Not tested again |
|---|---|---|---|
| 5–8 years | 552 | 1.1% (95% CI 0.5–2.4) | 6.7% (95% CI 4.9–9.1) |
| 8–12 years | 1,153 | 0.61% (95% CI 0.3–1.2) | 9.0% (95% CI 7.5–10.8) |
| 12–16 years | 1,097 | 0.64% (95% CI 0.3–1.3) | 23.7% (95% CI 21.3–26.3) |
| 16 years and over | 1,025 | 0.39% (95% CI 0.2–1.0) | 35.1% (95% CI 32.3–38.1) |
An age-standardised same-item rate is withheld because at least one age band sits below the 300-car floor. The crude rate in the answer box is still the all-fuels figure. Remaining bands are not re-weighted.
By mileage at the 2024 test
Scroll horizontally to read every mileage column.
| Mileage | Cars | Same-item fail | Not tested again |
|---|---|---|---|
| Under 40,000 miles | 446 | 0.90% (95% CI 0.3–2.3) | 9.2% (95% CI 6.8–12.2) |
| 40,000–80,000 miles | 1,114 | 0.45% (95% CI 0.2–1.0) | 8.9% (95% CI 7.4–10.7) |
| 80,000–120,000 miles | 1,278 | 0.63% (95% CI 0.3–1.2) | 19.8% (95% CI 17.7–22.1) |
| 120,000 miles and over | 1,205 | 0.58% (95% CI 0.3–1.2) | 31.6% (95% CI 29.1–34.3) |
By month of the 2024 test
Calendar month of the 2024 index test, among months with at least 300 cars in this fail cohort. Same-item fail is the share that failed on this wording again in 2025. Not tested again is the share with no later Class 4 test in 2025. This is a 2024 snapshot split, like age and mileage on this page. It is not miles between tests. It is not the all-fuels same-item rate already on this page. Months below that floor are omitted, not shown as zero.
Scroll horizontally to read every month column.
| Month | Cars | Same-item fail | Not tested again |
|---|---|---|---|
| January | 409 | 0.49% (95% CI 0.1–1.8) | 21.8% (95% CI 18.0–26.0) |
| February | 337 | 0.59% (95% CI 0.2–2.1) | 18.4% (95% CI 14.6–22.9) |
| March | 393 | 1.0% (95% CI 0.4–2.6) | 18.6% (95% CI 15.0–22.7) |
| May | 301 | 0.33% (95% CI 0.1–1.9) | 16.6% (95% CI 12.8–21.2) |
| June | 305 | 1.3% (95% CI 0.5–3.3) | 14.8% (95% CI 11.2–19.2) |
| July | 343 | 0% (95% CI 0.0–1.1) | 15.2% (95% CI 11.8–19.3) |
| August | 307 | 0.65% (95% CI 0.2–2.3) | 18.9% (95% CI 14.9–23.6) |
| September | 325 | 0.92% (95% CI 0.3–2.7) | 15.1% (95% CI 11.6–19.4) |
| October | 447 | 0.22% (95% CI 0.0–1.3) | 19.0% (95% CI 15.6–22.9) |
| November | 364 | 1.4% (95% CI 0.6–3.2) | 22.3% (95% CI 18.3–26.8) |
By engine size at the 2024 test
Cylinder capacity of the 2024 index test. Among bands with at least 300 cars in this fail cohort, the same-item fail rate in 2025. Each row is that engine-size band only. It is not the all-fuels same-item rate already on this page. Bands below that floor are omitted, not shown as zero. A missing or zero capacity is withheld, not folded into the smallest band.
Scroll horizontally to read every engine-size column.
| Engine size | Cars | Same-item fail |
|---|---|---|
| 1001-1400 | 438 | 0.46% (95% CI 0.1–1.6) |
| 1401-1600 | 1,131 | 0.97% (95% CI 0.5–1.7) |
| 1601-2000 | 1,472 | 0.41% (95% CI 0.2–0.9) |
| 2001-2500 | 395 | 0.51% (95% CI 0.1–1.8) |
| 2501+ | 442 | 0.45% (95% CI 0.1–1.6) |
A robustness re-run on the 2,024 cars tested in January–June 2024 only — so the next annual test almost always falls inside 2025 — found a same-item fail rate of 0.64% (95% CI 0.4–1.1) and a not-retested gap of +11.1 points versus the first-half control. A December 2024 test may not be due until 2026, which can make a car look as if it vanished; the first-half window removes most of that censoring.
Other brakes failures
How the follow-up is done
DVSA’s annual anonymised extracts keep a stable vehicle_id, so the same physical car can be compared from one year to the next. This page uses the earliest 2024 normal test (test type NT) that failed on this line, then looks for a 2025 failure with the same wording. Pages are published only where the 2024 fail cohort is at least 500 cars. Full method, including Wilson intervals and age-standardisation: how these figures are calculated. Registry: MOT prognosis registry.
Source: DVSA Anonymised MOT tests and results, 2024 and 2025 extracts (Class 4). Repeat rate = cars that failed on this wording again in 2025 ÷ unique cars that failed on it at their first 2024 normal test. Contains public sector information licensed under the Open Government Licence v3.0.