[peralfaadastra]

We all know that stop/start can be pretty elusive at the best of times and most of us are happy when it goes AWOL, but that usually happens without any specific warning message appearing. However, I have this "Stop Start Not Available" warning, alternating with a red battery icon. I've charged the battery fully with my CTEK and driven it for a week or so since, but the warning won't clear. One time, before I charged it, when I pulled up at lights, the engine did stop, but then didn't restart when I lifted off the brakes and I had to restart on the button. On another occasion, after charging, again at some lights, it stopped, restarted normally when I took my foot off the brakes and the Not Available warning immediately reappeared. HRW and heated seats are still working OK. Just measured battery voltage as 11.98 volts, car having stood for 24 hours. Other than the annoying warning message, the car drives perfectly normally.

Anybody got any ideas? Will it eventually go away of its own accord, or do I need to have a reset to get rid fo it?

 

[Andy Bowden]

It would seem the car thinks there's something wrong with the battery, despite the fact you've charged it, or the alternator.
Probably a good idea to use MultiECUscan or some other OBD scanner to see what DTC codes have been logged.

 

[peralfaadastra]

It would seem the car thinks there's something wrong with the battery, despite the fact you've charged it, or the alternator.
Probably a good idea to use MultiECUscan or some other OBD scanner to see what DTC codes have been logged.

Thanks for the response Andy. The owner's manual says that the battery icon indicates an alternator fault, but as the battery charge seems to be holding up, maybe the warning itself is spurious. It's still under warranty, so maybe I'll have to get it looked at by the dealer.

 

[Dan88]

Are any other warning messages showing?

 

[peralfaadastra]

Are any other warning messages showing?

Just the red battery icon, alternating with the S/S warning. Presumably it's the battery (alternator) fault that disables S/S. Posting this has helped clarify my own thoughts and I suspect it's the latter that's the problem, whether real or not.

 

[Domhnall Dearg]

I had that exact situation on my 2017 Veloce. It was diagnosed to corrosion in the wiring loom in the driver’s side wing, which seems to be a common fault with seemingly random symptoms.

 

[John_spider71]

I had this issue -faulty starter relay (in the boot under the floor). In some cases the car wouldn’t restart at all.

 

[alfaitalia]

11.98 volts is pretty much flat.......its only about 40% charged at that voltage.

 

[Andy Bowden]

11.98 volts is pretty much flat.......its only about 40% charged at that voltage.

So long as there is no current flowing from the battery. If the measurement was taken with some circuit(s) live, the state of charge might have been somewhat higher than that.

 

[TheColonel]

Here's a chart I found somewhere relating battery voltage to state of charge - but as Andy says, this is no-load voltage, i.e. no current being drawn from the battery.

 

[Andy Bowden]

If my understanding of the Giulia's thresholds are correct, using that table one needs an off load / off charge battery voltage of >=~12.4V for S/S to work and >=~12.2V for the HRW.
Even then it is the BCM/IBS's assessment of the SoC which is used. That assessment uses an integration of the current in/out of the battery over time as well as voltage. So even if the battery off load is 12.5V, one can't be 100% sure S/S will work.

 

[peralfaadastra]

Thanks to everybody for your input. To update, I put the CTEK on over Friday night and have been out for a couple of runs since, one short one on Saturday, one longer (15 miles each way) on Sunday. Measured the battery voltage again immediately on return and it's at 12.5V, so better than before, but have put the CTEK back on just to make sure.
When I first posted I suspected that it was down to what we know to be a somewhat temperamental S/S and charging system and had driven the car for some days hoping that once the system realised that the battery was fully charged the fault would clear. However, it hasn't and I believe that there is a fault somewhere - alternator, wiring, relays, whatever - and it will have to be looked at under warranty. Given that the battery voltage doesn't fall dramatically with use (even if it is lower than ideal), it doesn't seem likely that the alternator has packed up completely, but there's something amiss.
If and when I get it resolved, I will report back on the cause, which will at least add something to our fund of knowledge.

 

[TheColonel]

One point to note about measuring battery voltage to determine state of charge. If you've been charging the battery, which you will have been if you drove it, then the battery needs to 'rest' for several hours to give a true indication of SOC. While charging, the charging circuit applies a slightly higher voltage to the battery (up to 14V in a car) and the battery holds a residual part of this for a while. So I'd suggest re-measuring the voltage after a few hours at rest to get a true SOC reading.

Keep in mind too that voltage varies a little with temperature.

 

[Dugup]

I had a similar issue twice. The car wouldn’t start. It sounded like the starter motor was ticking over but engine not responding. I spoke to my Alfa mechanic, after the first time, and he thought I may have flooded it but when it did eventually start the ignition and ‘start stop not working’ warnings came on. I took it to the mechanic who plugged in the diagnostic thing and said the start stop relay was showing a fault so he reset it and was ok until it happened again recently - nearly a year later.
Any ideas?

 

[Andy Bowden]

Various posts in other threads about defective relays.

 

[Dugup]

Yes thanks. Some say it’s a good idea to carry a spare relay. I think I’ll do that if I can get my hands on one.

 

[peralfaadastra]

Coincidentally, a friend in the Owner's Club has just acquired the gubbins to access the error codes and (hopefully) to bypass the block that Alfa added to the system so that codes can be reset, so once the weather improves a bit we'll try to find out exactly what is happening. I've boned up on the posts regarding start relay issues, but mine starts on the button without any problems, so don't think it's that.
I did come across a post where a wire had detached from the "stop/start sensor" at the battery negative post, resulting in the stop/start not available warning. Does this just measure battery voltage?
Wondering now whether I shouldn't just change the battery anyway, as responses above to my voltage measurements suggest that it's not as healthy as it should be, even though it seems to have enough juice to run everything except stop/start.
If it goes in to the dealer and they find that it's the battery they'll charge me 160 quid for the diagnostic investigation and the battery's out of warranty as it's >3 years old, so I'll have to stump up for that as well.

 

[Andy Bowden]

My battery is 6 years old and no sign of it needing to be changed. I probably will change it in the autumn, if I'm keeping the car though another winter.

 

[peralfaadastra]

I had this issue -faulty starter relay (in the boot under the floor). In some cases the car wouldn’t restart at all.

I tried swapping the relays around in the module in the boot, but it didn't get rid of the warning.
On my way home yesterday the fault did clear briefly and I had a joyous moment when I thought all was well again, but it came back again after a couple of minutes. Checked the battery voltage again and it's still at 12.6V, so still don't think that's where the problem is. I'm hoping to get the fault codes checked later this week.

 

[Andy Bowden]

I'm hoping to get the fault codes checked later this week.

I suggest if possible you use software / a device which can access the BCM and read its State of Charge assessment as well as checking the error codes. The free version of MultiECUscan would do this. BCM needs to see >80% SoC for S/S to work.
My feeling is your BCM is assessing SoC as around 80% and S/S is sometimes available, sometimes not.