Idle-Stop not working ... cold weather or fault ?

[guest1372]

Our ex-family fleet Alfa would not auto stop unless the steering was exactly straight ahead, I assume this was to assist with joining a fast road from a side road.
... and Honda have been building cars with 'recallable' airbags while performing recalls of older cars first due to limited production capacity at suppliers.
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TG

[Downsizer]

9 degrees centigrade, and after a 20 mile run in sunshine with no Air con the auto stop still doesn't operate, showing the battery symbol.  Perhaps it's a Russian cyberattack!

[ColinB]

9 degrees centigrade, and after a 20 mile run in sunshine with no Air con the auto stop still doesn't operate, showing the battery symbol.

That's pretty similar to what I'm seeing. Although it has actually improved, instead of not working at all, it now functions maybe 10-20% of the occasions when I expect it to.

[John Ratsey]

9 degrees centigrade, and after a 20 mile run in sunshine with no Air con the auto stop still doesn't operate, showing the battery symbol.  Perhaps it's a Russian cyberattack!

The first journey may charge the battery but my hypothesis is that car won't realise that the battery is now fully charged until the next journey as I think it checks the charge status when the engine is started.

[Skyrider]

My car is used daily, a mixture of local pottering and at least 30 minutes motorway or NSL roads two or three times a week. I have only seen the low battery indication for no stop start a couple of times. I charge my battery most weekends during cold weather, it can take surprising length of time to fully charge with a variable rate smart charger with maximum of 5 amps.

[andruec]

Mine definitely relates to the fan. If it's on three or more bars the I/S won't operate. I assume that once the weather warms up a bit the climate control won't need the fan on so high for so long and I/S will start operating more frequently.

[ColinB]

None of those suggestions would seem to account for a mix of working and not working with a low battery indication in the course of a single journey. Fan on 1 or 2, vent switch NOT set to demist screen. Nor why a battery with a measured voltage of 12.7V produces a  low battery warning.

[Skyrider]

If it is any help, my car has done a 20 mile round trip this morning, and a ten minute local potter this afternoon. My manual air con has been off with the fan on position 2 throughout. The stop start is working perfectly. I have just checked my battery voltage, it is 12.6V. The battery has not been on a charger for over a week.

[andruec]

Turns out it's not the fan speed. I/S was working just fine tonight with the fan on 3. It is milder and drier tonight though.

[Skyrider]

Turns out it's not the fan speed. I/S was working just fine tonight with the fan on 3. It is milder and drier tonight though.

That makes sense, the alternator sustains the cars electrical load and charges the battery with any spare output. I would be surprised if the alternator has less than about 80amps output.

[andruec]

Turns out it's not the fan speed. I/S was working just fine tonight with the fan on 3. It is milder and drier tonight though.

That makes sense, the alternator sustains the cars electrical load and charges the battery with any spare output. I would be surprised if the alternator has less than about 80amps output.

So the mystery is what was my climate control doing this morning when it was 3 degrees, and I'd driven over 8 miles at 50mph, that it wasn't doing this evening at 10 degrees when I'd only driven a mile or so in rush hour traffic 

[Skyrider]

Anybody's guess what your climate control was up to, the cars computers will know, but I think you are making the mistake of trying to pin down one reason for the stop start not activating. I know that one of my previous cars had about 15 parameters that had to be met for the stop start to activate. The heated rear window was one thing which would deactivate it. There is a post up thread somewhere about the multitude of things that deactivate it. These days the car knows more about its operating procedures than the owner, let it do its own thing. You will know when it is broken, the wheels will not go round. :-)

[andruec]

These days the car knows more about its operating procedures than the owner, let it do its own thing.

Sorry. You're talking to a computer programmer. 'Let it do it's own thing' is not a concept I can be happy with 

[Skyrider]

These days the car knows more about its operating procedures than the owner, let it do its own thing.

Sorry. You're talking to a computer programmer. 'Let it do it's own thing' is not a concept I can be happy with 

Ok, take the computer to bits and find out what it is doing, or get the specifications and programs for the cars computers. As an IT expert you should know better than trying to guess what a computer or three are doing. :-)

[ColinB]

These days the car knows more about its operating procedures than the owner, let it do its own thing. You will know when it is broken, the wheels will not go round. :-)

Only up to a point. Personally I don't like a car that isn't behaving predictably, because if it isn't that can be an early indication of a fault that I want to get fixed before the wheels stop turning. After nearly 18 months of driving it I know where, on my usual trips, I can expect the I/S to function and in general it's done that. Now, for no apparent reason, it's not doing that so I want to know why.