This morning my engine light came on when driving. Or, to be more precise, when I accelerated to clear a set of lights.

The light staid on, but didn't affect performance,. After about thirty seconds it went out.

Evoscan link displays no fault codes.

Visual inspection of all the cabling in the engine bay, no loose connections or bad wiring. No recent mods to the car, no recent work to the car either. Car has sat in the shed for the last two days - hasn't been driven. This engine light issue appears to be unprovoked.

I'm replacing the engine soon, so I want this issue sorted before then. Any ideas?

Hope that it pops up again and scan it while it's up?

So what errors can occur that throw a CEL but aren't recorded in the ECU? (oxygen sensor? MAF?)

As above, if it comes back, try to track it down. If it doesn't, all good.

Unfortunately I don't trust Evoscan's reporting of fault codes from Magnas (though I can only say this from limited experience) and would much rather use the flashing lights method in the absence of a MUT system.

I ended up cleaning all of the electrical connections, and have a good two hour poke around in the engine bay. Just cleaning and checking.

Didn't find anything out of the ordinary.

Test drives today didn't bring up the CEL again.

I've had an oxygen sensor fritz out on me before and it doesn't throw a CEL. A dodgy MAF will though... so, I cleaned mine today.

Evoscan has picked an error code for me before. Not this car, my GTVi. A transmission error? Aside from that, no, Evoscan doesn't seem to pick up engine codes. Not for me anyway.

I'll look into things a bit more when the engine is out.