Which dashboard warning lights fail an MOT?
Since 2018 the MOT uses the car's own warning lights as part of the test. If a safety system is telling the driver it's faulty, the tester fails it.
Checked against the MOT inspection manual and GOV.UK guidance · Updated November 2026
| Warning lamp | MOT result if lit | Common cause | Typical fix |
|---|---|---|---|
| Engine management (MIL / EML) | Major | Sensors, misfire, EGR, DPF, catalytic converter | £60–£1,500+ |
| Airbag / SRS | Major | Under-seat connector, clock spring, seatbelt pretensioner | £50–£500 |
| ABS | Major | Wheel speed sensor, reluctor ring, ABS module | £80–£1,200 |
| ESC / ESP (stability control) | Major | Often shares a fault with ABS; steering angle sensor | £80–£600 |
| Brake fluid / brake system | Major | Low fluid (worn pads or a leak), sensor | £10–£300 |
| Brake pad wear | Major | Pads at minimum | £70–£350 |
| Electronic parking brake | Major | Caliper motor, switch | £100–£500 |
| TPMS (cars first used from 1 Jan 2012) | Major | Sensor battery, damaged sensor, relearn needed | £0–£90 per sensor |
| Power steering (electric) | Major | Torque sensor, motor, low voltage | £80–£1,200 |
| Main beam / indicator / rear fog tell-tales | Major if not working | Bulb or switch | £5–£80 |
The bulb check
Most warning lamps light briefly when the ignition is switched on, then go out. The tester watches for this. A lamp that never lights – because someone has removed the bulb or the cluster is faulty – is also a fail, since the system can't warn the driver.
Don't just clear the code
Clearing a fault code with a cheap reader right before the test is pointless: the tester will often notice, the fault usually returns within a few minutes, and many systems' readiness monitors show the codes were recently cleared. Diagnose and fix the cause.
Engine management light
The engine malfunction indicator lamp is a major fail whenever it's lit. The cause can be anything from a £30 sensor to a £1,500 DPF. Get the fault codes read first (many parts shops do it free, garages charge £40–£90), then price the repair. See emissions failures.