Stop/start only flashes, never actually works

[robadob]

I have had a 2016 DS3 BlueHDI 120 S/S Prestige for one week now and the stop/start hasn't worked yet, the eco light only flashes. From the manual and reading online my understanding is that this means the system is working but some factor has stopped it from initiating. I found the following document which lists all the potential reasons why this might be (https://docdro.id/iy4Cw2h).

At first I figured that it was because the battery was low on charge (the date was set at 2013 when I first turned it on so I thought it might have been flat at some point) or it needed a long run to clear the DPF. However, in the last week I have done 700 miles, some journeys over 3 hours of continuous driving and it still just flashes.

My partner owns a 2015 plate DS3 BlueHDI 100 S/S DStyle and in the same weather conditions her S/S works perfectly, therefore I do not think it is a temperature related issue.

I am going to try and get my hands on a multimeter to test the battery in case the voltage is too low, but does anyone have any ideas what it could be?

[BeefMasta]

There are approximately 70 checks that the stop/start system does before stopping. In the winter it will usually not work due to the cold / dark.

If the light is flashing it means the system is working but the parameters haven’t been met to allow the system to stop/start.

[robadob]

There are approximately 70 checks that the stop/start system does before stopping. In the winter it will usually not work due to the cold / dark.

If the light is flashing it means the system is working but the parameters haven’t been met to allow the system to stop/start.

Thanks for your reply. I realise that there are many things that can affect it (see my linked document, if there is a more exhaustive list please let me know).

However, of those ~70 parameters, some are out of your control (like the weather) and some are within your can control (like the battery). As in the exact same weather conditions stop/start works in an almost identical spec DS3 (my partners), I don't see how these can be the weather/temperature parameters stopping it from working.

Therefore, it seems like it is more likely to be a component issue within the car, such as the voltage or state of charge of the battery. However, as it has just gone through a full service I would have thought a faulty battery would have been detected. This is why I was asking if anyone had any other ideas what could be causing the system to not activate.

[peter m]

Could well be the battery causing stop/start issue was the case with mine . Battery replaced and no issue with stop/start. Mine wasn't holding a good enough charge.

[robadob]

The no load battery voltage (after a few minutes with the headlights on to remove the surface charge) was 12.06 V. After starting the engine, this increased to 13.7 V. This seems to be ok and indicates it is charging. I'm going to check it again after a long drive when the battery should be fully charged and be about 12.6 V under no load.

Could well be the battery causing stop/start issue was the case with mine . Battery replaced and no issue with stop/start. Mine wasn't holding a good enough charge.

Peter, were they any other symptoms when your battery didn't hold enough charge?

[Chris_Blue]

Mine doesn't work any more..... thanks f**k for that.
PITA

[robadob]

Had a battery health check at a garage today and it failed, they also flagged a potential issue with the alternator not charging the battery properly. I'm taking it back to the dealership so they can investigate.

[peter m]

The no load battery voltage (after a few minutes with the headlights on to remove the surface charge) was 12.06 V. After starting the engine, this increased to 13.7 V. This seems to be ok and indicates it is charging. I'm going to check it again after a long drive when the battery should be fully charged and be about 12.6 V under no load.



Peter, were they any other symptoms when your battery didn't hold enough charge?

Symptoms and battery voltage were similar to what you have . Battery voltage would be good whilst engine running but after engine stop would rapidly drop to below 12.4 volts ,once battery replaced stop start worked perfectly.

[robadob]

Got a new battery fitted, stop start immediately started to work. Just like Peter M.

Heads up for when this happens to the person in the future reading this, get a battery health check. It should be free at Mr Clutch, Kwik fit, halfords etc.