The engine management light was on with the engine running. It's a straight failure regardless of how the car drives — the MOT doesn't care what the fault is, only that the system is reporting one.
Wording as it commonly appears on an MOT certificate: “Engine malfunction indicator lamp indicates a fault”.
What does it mean?
The engine management light was on with the engine running. It's a straight failure regardless of how the car drives — the MOT doesn't care what the fault is, only that the system is reporting one.
How serious is it?
Usually recorded as: Major. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- Anything the engine management system monitors — sensors, misfires, emissions systems, EGR, DPF
- A fault cleared before the test that has simply come back on the drive to the test station
- A genuine mechanical fault the light is correctly warning you about
What a mechanic would check
Read the stored codes and the freeze-frame data, which tells you the conditions when the fault set. Codes point at a circuit, not a part — a code naming a sensor is as likely to be wiring or the thing the sensor is measuring. That's the difference between a repair that works and parts-swapping.
What might need replacing
- Whatever the diagnosis actually shows — this genuinely cannot be predicted from the light alone
Can you still drive it?
A steady light generally means get it looked at soon; a flashing light usually means a misfire that can damage the catalyst, and you should stop driving. Either way it's an MOT failure, and clearing the code without fixing the cause just means it fails again.
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This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.