No, don't ignore it. The light going off doesn't mean the fault has cleared — it means the ECU has decided the fault isn't currently present, but the fault code is still stored. A diagnostic scan will read it. Most common causes: a misfire, a dodgy MAF sensor, or an early O2 sensor fault.
This is the question I probably get asked the most. Driver sees the orange light pop on, panics, then it goes off the next day and they think they're in the clear. They're not — and here's why.
Will the fault code clear itself? — The light might go out, but the code stays in memory for around 40 drive cycles (a week or two of normal driving) before the ECU wipes it. So even if the light's off today, a scan tomorrow will still show what happened.
Can I just disconnect the battery to clear it? — You can, but you've solved nothing — the fault will come back next time you drive. And on a lot of modern cars, disconnecting the battery loses your radio code, window memory and steering angle reset. Get it scanned properly.
Is it safe to drive with an intermittent EML? — Usually yes for short trips. If the light is steady amber, drive carefully and book it in. If it's flashing, stop — that's an active misfire and you'll wreck the catalytic converter within minutes.
Bob's Mechanical Repairs — independent family-run garage in Birnam, Dunkeld, Perthshire. Call 01350 727 276 or email [email protected].