05 1.9 Intermittent Electrical Fault - Klingon
Wife's car has started to have the above. On Tuesday, car was fine until having parked. Then a 1/2 hour later, tried to start car then but after pushing button, would not tick over or fire up at all, stop would come on with electrical fault message. Further attemtps to start car were fruitless. Left car for 3-4 hours then starts no problem. Same thing happended again Wednesday having parked and then trying to re-start a few moments later.

I've take the car into a renault accredited service centre to undertake a diagnostic but my bet is it will not tell them anything. Having trawled this forum and the internet it seems that renaults are famed for electrical problems. I've seen anything from change a fuse to changing the ECU which appears to be a costly job.

I know it is difficult for anyone to give an opinion on this but someone may have an idea should the service centre come back with nothing or want to change the ECU. Both days have been very hot as you all know so I don't know whether this will have anything to do with it. I asked the wife and no other warning lights were on at the time of the warning message. I haven't seen the problem first hand so I cannot give any more details.

05 1.9 Intermittent Electrical Fault - Vinnychoff
i have seen that some of the electronic fobs can be faulty even if the battery in the fob is not fully charged....happened on a motor bike i owned.
it might be an idea as you say to eliminate..weather. try to start in warm condition and cold later at night. in the spot it was parked was the car in direct sun?
intermintent faults are the hardest to find although if there was error codes these are stored and can be retirieved from the data with tools....