Stop start problems

Upzeecreek

Just wondering if anyone can shed some light on what might be causing an intermittent problem with the stop start. Car is a 2013 1.4 Auto Golf. Fully serviced . Over the last year it has been giving trouble restarting after engine cuts out. Always restarts first time when manually restarted. Tends to happen when engine is up to temperature. Could it be that battery needs replacing? I thought the engine would not cut out if battery not charged ? VW have looked at it and can't find any faults and have just said car needs to do long journey but problem still presents even after a long journey. 
Any thoughts on what might the problem be? Thanks 

daveyjp

The logic to start from manual will be different from a stop/start restart.

If its like my auto for a manual start the car will be in Park and the brake pedal needs to be pressed.  Only then will it start.

A stop start will be activated when you come to a rest in Drive and keep the brake depressed.  The car restarts when the brake is released.  If your car isn't starting from this scenario it may be nothing more than a worn brake pedal switch and the signal to restart isn't being received when the brake is released.

TadleyBaggie

I had a faulty battery on a Qashqai, that eventually completely died. The first symptom was that start/stop never kicked in when I expected it too.

Upzeecreek

daveyjp said:

The logic to start from manual will be different from a stop/start restart.

If its like my auto for a manual start the car will be in Park and the brake pedal needs to be pressed.  Only then will it start.

A stop start will be activated when you come to a rest in Drive and keep the brake depressed.  The car restarts when the brake is released.  If your car isn't starting from this scenario it may be nothing more than a worn brake pedal switch and the signal to restart isn't being received when the brake is released.

The weird thing is ,it only seems to do it when engine is up to temperature. If it was a brake pedal switch, I would presume it would fail to restart when engine cold too.

neilmcl

Upzeecreek said:

daveyjp said:

The logic to start from manual will be different from a stop/start restart.

If its like my auto for a manual start the car will be in Park and the brake pedal needs to be pressed.  Only then will it start.

A stop start will be activated when you come to a rest in Drive and keep the brake depressed.  The car restarts when the brake is released.  If your car isn't starting from this scenario it may be nothing more than a worn brake pedal switch and the signal to restart isn't being received when the brake is released.

The weird thing is ,it only seems to do it when engine is up to temperature. If it was a brake pedal switch, I would presume it would fail to restart when engine cold too.

Doesn't sound like the battery, the stop/start system wouldn't activate in the first place if the battery is undercharged nor would it come on when then engine is cold. Maybe it's a sensor issue or a problem with the starter motor. Having said that, given the age of the car, you're probably due a new battery anyway so you might want to start there.

Brewer20

Get your battery checked as a first action.
I had a fault, car going into limp mode. which at the time I wouldn't have related to a faulty battery. I had the local garage take a look over it, he hooked his diagnostic gizmo to it and it told him some nonsense about a sensor. He cleared the codes and then checked the battery, yep he found it to be below par even after I'd given it a long run. Only just over 4 years old but the battery had started to give up 
New battery sorted my problem and his final words on the VAG group cars, they throw up some weird codes or perform some weird things, most of those are battery related, I've seen loads of cars like it.

Upzeecreek

Plan to get the battery changed next week so will report back. 
Thanks for all the helpful tips. 

Stubod

I have a 1.4 VAG (Yeti) with stop/start and it has hardly ever worked, (always starts first time on the key).

I understand that the stop / start system is programmed not to operate if the battery is low, or the temp is too low or you have a lot of electrics on (eg lights / aircon / heated seats etc)?

molerat

Stubod said:

I have a 1.4 VAG (Yeti) with stop/start and it has hardly ever worked, (always starts first time on the key).

I understand that the stop / start system is programmed not to operate if the battery is low, or the temp is too low or you have a lot of electrics on (eg lights / aircon / heated seats etc)?

The problem for op though is the stop part is working fine, it is the start when hot that isn't.  I suspect they need to find a VW dealer, or good indy, that knows what they are doing.

chrisw

I don't think it's the battery. Normally batteries struggle when cold rather than hot. And the OP hasn't said, but I presume it's turning over fine but just not firing. Certainly sounds more like a sensor issue, possibly crankshaft or camshaft sensor breaking down when hot?

Upzeecreek

When I take my foot off the brake to move off ( and the car would normally restart) it just does nothing . It doesn't even try to turn over and restart. I have to them put it into park and restart manually. It restarts perfectly with a manual restart.