yellow or amber engine management light (EML)

[Alphie]

Does anyone know how to read the cause of the EML coming on. It seems to only do it on warm days & if I stop the engine & immediately restart it, it resets & stays off, makes me think the trigger may just be a momentary fault but that the light latches on until the engine is powered off.
It was an infrequent event but now happens on most longish journeys. There is no apparent loss of power or anything else noticeable. If you google it - it can mean a number of things. Just wondering if anyone else has experienced same & thereby work out which on the list of possibles I should try first. [I am thinking dirty mass airflow sensor] Thanks

[Gamith]

Mine was in need of a replacement Fuel Oxygen sensor, the front one in the exhaust manifold. If you have an OBD reader it might help, my code was a P0171 system too lean (Bank 1). It would drive for a while with no light and then come on. There was a distinct smell of petrol from the exhaust.

[Alphie]

Thanks Paul, that's useful & presumably means it using excess fuel in that condition. I've borrowed a basic OBD & will give it a try. Mine runs on LPG most of the time once started on petrol but I'll also check the exhaust when the light is on.

[Gamith]

The OBD tool will need to support JOBD as its a version that looks to be specific to Japan, so don't be surprised if you don't get any readings from it. There is at least one post talking about compatible OBD tools, so could well be worth finding that. 

Oh and yes it was using more fuel as the engine thought it was running lean and kept on putting more fuel in the mix. Anyway I cleaned the MAF, which made no difference, and then replaced the sensor, which was a pain as the previous person had broken the thread and I had to get a new tap and die (M18 x1.5) to cut the thread out again.

Edited April 6 by Gamith
To add bit about fuel and sensor.