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start/stop not always working?

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21K views 20 replies 13 participants last post by  chiptivo  
#1 ·
Hi there,
I have only had my V40 for around a week and only driven it 3 times so far.
the first time the start/stop never worked at all. Yesterday it was working, which was great.....then today it decided not to work again.
Is there something wrong with the electrics in the car or is this something to be expected?
Thanks in advance
 
#2 ·
Hi,
I had the same problem about 5 weeks ago when i bought mine, I took it to Volvo and they said the battery was slighty low in juice and needed to drive it a bit to get it fully charged and it would be ok, and it is :). Something to do with the amount of energy it takes to keep starting the car. Hope this helps could be something different for you lets hope not.
 
#6 ·
Hi.

Are you doing short journeys. The stop/ start battery is a second battery and is much smaller than the main one.

When we first got the car I'd just sit in it with the engine running in our driveway for 1/2 an hour or so. That seemed to help.

I'm just nervous of the stop/start function. I've got an underlying worry that the car won't start again in the queue of traffic.
 
#7 ·
I had the same issue of start/stop not being available and low battery warning messages popping up every so often
Like most of us car has been limited to short journeys over the past year
Solved issue by putting battery on a trickle charge for a few hours
Fingers crossed battery will last another 6 months before we hand car back at end of lease
 
#8 ·
There are a few reasons, if you go into the Driv-E options on the car settings it will tell you if start stop is available or why not.
There are a number of reasons:
1. The battery charge is low
2. The engine is cold
3. There is too much power draw from the batteries (usually in winter if you have lights, heated seats, heated screens on)
4. On very warm days if there is demand for fans or aircon
5. If you have a diesel and the engine is doing a dpf cleaning cycle.

As this week is quite warm, you are driving short journeys and the car might have been on the forecourt for a while more than one of the above conditions could all be interacting.
 
#10 ·
A long run will give the battery a charge, and will bring the engine up to temp. I find on hot days it does kick in but only keeps the engine off for about the time the traffic lights change twice (in a queue) before the demand for the AC causes it to restart.
 
#12 ·
There is a while thread on hidden features. Things like dimming the map lights, the coloured theatre lights, internet radio, hidden seat pockets, it just depends on the model year and trim level
 
#13 ·
It may take over an hour at speed to charge the battery sufficiently for it to have enough charge in both batteries for the S/S to work. Before lockdown, the car almost always had S/S avaliable, I would use the car then everyweekend, and once during the weekdays. During lockdown months, the S/S rarely worked, also I rarely used the car. If you started the car on a cold morning, it is unlikely for S/S to work even if your battery charge is high enough, likewise when it's over 30 degrees, it S/S never engages.
 
#14 ·
Driving at speed doesn't really help. Cars with start/stop have smart alternator systems. They do most of their charging on the overrun (throttle closed) or when braking. When using the throttle to propel the car forward or maintain speed the amount of charge is throttled back to reduce the load on the engine and minimise emissions. The battery management system maintains the battery at around 85% SOC to allow for charge from the smart alternator to be stored and re-used at the next engine stop event, but it also means that the battery has less overhead available before it reaches the floor at which the system shuts off start/stop to maintain the battery SOC.

The best thing you can do for your mental well being is not worry about it, and let the car work it out for itself. It will work when the ECUs decide they want it to, and not when they decide otherwise. Just let the car do it's thing ;)