I have had this car in to the dealer 4 times, the last for almost 2 weeks and to a second opinion from a mechanic who services my husband's Porsche. The dealer has changed the battery 5 months ago. The car started fine after that for about 3 months. Since then it has failed to start many times and after a trickle charge starts. The dealer says it starts every time they have it and said they have checked the electrical and there are no problems. Our second opinion had it for about 5 days and it did not start 4 times. The latter suggested we take it back to the dealer for a longer check and dx. We left on a 2 week trip, renting another car. The dealer had it for about 13 days and said it started after a rest period of 5 days and there was no problem. We've had it home for 2 days, yesterday it started, today it does not. I took a video and there was an ABS fault flash on the screen. Thanks for any suggestions.

 

Battery health is easy to check with a load test. Battery drain with the ignition off is also easy to test with a current leakage test.

Sometimes the battery is tested at the battery posts and checks out fine. If the battery is checked at the cables the defect is discovered: cable end corrosion creating high resistance in the join between the post and the inside of the cable. In any event, testing the battery, the electrical system and the charging system properly must reveal the fault.

Make sure your car has been flashed with the latest software update for your model year. Some problems were encountered with the ICE system not switching off properly and draining the battery.

Frankly, there is no way this cannot be diagnosed easily by a competent shop who understands how these cars work.

 

Emi, the next time the car will not start, I want you to try something. Open the driver's door and then attempt to start the car. As you are pushing the button to start, watch the overhead light. Does the light remain bright, dim slightly, or does it go out completely? Going out completely would be a good sign that you have a battery cable issue. If the light remains bright, then there is most likely a computer issue and the necessary signals are not making it to the correct place. If the light dims and the car will not start, then odds are you are looking at a bad starter (possibly a bad battery cable).

The other question that I would have is whether the car seems to have more problems starting after it has been driven and only stopped for say 10 minutes (like you went into a store and then came right back out) or if the problem occurs more often on the first start of the day (ie, motor cold). That may help narrow down the ultimate source of the problem.

 

Post a link to the video too.

 

Thanks to all suggestions, found Jeff at British Performance in Mission Viejo, CA who, puzzled out my problem, took the battery out and the next day found it down by 23%. So, even though the battery was only 6 mos. old,it was faulty. Replaced battery and all is well.
Thank you!!!