General Stop/Start not working

[jackdow98]

Hi all,

I am a returning Fiat 500 member having just purchased my 5th - This time a 2012 500C Lounge TwinAir.

Upon purchasing the car I had the battery tested as the Stop/Start was not working. The health of the battery (being the original) was essentially 0% and so I have now changed the battery for a new one.

I understand that the car needs time to communicate with the new battery, however the stop/start system is still not working almost a week in. The car does automatically restart if stalled.

Additionally, on Sunday night I got in the car to a number of fault messages, including S/S unavailable, ESP unavailable, hill hold control unavailable. Upon turning the car on and off, these messages cleared and have not come back on.

Please can I ask if this sounds like a common fault and for possible resolutions?

Many thanks

 

[John202020]

Hi what type of driving do you do? A short journey to work or shops each day or an hour a day each way? I'd say its still a bit soon to assume a fault but do check the sensor wire is not broken going to the module on the negative bat terminal.

 

[AndyRKett]

Stop start on fiats is a fickle thing.

Did you get the correct stop start battery, was it connected correctly and in the right time, was the moon in the right position in the sky. Was Capricorn transiting Aries at that exact moment in time?

These are all important questions to answer. Given the age of the car I would have a good look at the battery monitor a black module that’s part of one of the battery terminals. On older cars like this it’s possible one of the wires has broken on the multiplug or that the battery monitor/sensor has failed. In some respects not working is not a bad thing unless you specifically do long (in time) journeys in heavy traffic were the stop start might start to save fuel, but if you even dare to look at the heating or air con controls the stop start will stop working again

 

[Pugglt Auld Jock]

If we accept that Fiat's stop Start system is better thought of as an expression of intent rather than a reliable feature then this still sounds like a battery in a low state of charge or with a problem. You say you've fitted a new battery but don't completely discount the battery until it's been tested. Is it an EFB or Gel battery? An "ordinary" old type flooded cell battery won't cut the mustard with stop start.

After the car has stood overnight (which allows the battery to "normalize") check the voltage with something like a multimeter. very roughly speaking you should see around or a little over 12.5 volts. If it's substantially below 12 volts it either needs charged or you've got a problem so charge it up, leave for a few hours to normalize and restest. Even better than a multimeter is one of the new fangled battery condition testers like the Topdon BT200 or Foxwell BT715 which will give a pretty definitive result almost regardless of charge condition.

Next you need to check charging. Again with the multimeter connected across the battery terminals start and run the engine at a fast idle - 2,000 rpm is plenty. You should now be seeing around 13.4 to 14.5 volts. This proves the alternator is capable of charging the battery. At the same time you should look carefully at the terminal clamps - are they tight and no covered in corrosion?

Many cars which use stop start require that a new battery is "introduced" to the car's ECU in a relearning procedure so that the battery condition monitor and charging regime can be reset for the new battery. I'm not too sure if this applies to Fiat but seem to remember reading somewhere that it doesn't. I'm only mentioning it because if it does, and a lot of the VAG stuff I mess about with do require this to take place, the new battery will quite quickly degrade.

 

[jackdow98]

Many thanks for your replies, i’m really grateful for your help. I’ll begin by checking the wire on the battery as at the end of the day, it is an 11 year old car now.

This is the battery I have fitted.

 

[Pugglt Auld Jock]

Many thanks for your replies, i’m really grateful for your help. I’ll begin by checking the wire on the battery as at the end of the day, it is an 11 year old car now.

This is the battery I have fitted.

65Ah capacity and with a 600 amp CCA that should do the job nicely. However don't discount that, although a new battery, it may still be the battery at fault. I'd think Halfords would be happy to stick a battery condition analyzer - like the two I mentioned above - on it and just verify there's no problem with the battery itself. Chances are it's going to be just fine but I like to eliminate the obvious first.

 

[AndyRKett]

any dates on the battery that indicate when it was manufactured ? they can sit on shelves for many years especially in places like Halfords where a niche fitment might only fit a couple of models and so the demand may drop as cars of certain years or configurations get older.


For example does the 500C need a more powerful battery than a normal 500, because of the power demand of the roof, when combined with stop start and electric power steering.

 

[jackdow98]

Thank you all, I will check these points tomorrow and revert back to you!

 

[Piccolo Nero e Bella]

Many thanks for your replies, i’m really grateful for your help. I’ll begin by checking the wire on the battery as at the end of the day, it is an 11 year old car now.

This is the battery I have fitted.

That EFB battery is equivalent to the one in my own 2012 500C Lounge which was fitted in 2017 and is still going strong. The roof doesn't make much demand on the power (and mine is opened practically every trip if its not actually raining!). A dry lubricant along the rails should keep it running smoothly and minimize drag.

There may well be a fault in something affecting the S/S; do you get the "Stop/Start Unavailable" message on the central display? I don't think anyone's mentioned the earth lead which, on a car as old as this in your environment, may well be corroded and would be best replaced regardless.

 

[Pugglt Auld Jock]

any dates on the battery that indicate when it was manufactured ? they can sit on shelves for many years especially in places like Halfords where a niche fitment might only fit a couple of models and so the demand may drop as cars of certain years or configurations get older.

That's a very good point Andy. Many batteries will be date stamped but you often have to look carefully for it.

Way back when I worked in the Firestone Tyre and Auto stores (think an early - and in my opinion better - version of the modern fast fit operation) batteries was a big part of our operation. We held a stock of batteries which covered most common applications, looked very similar to what you see in a present day Halfords branch. My responsibility was to the workshop and the batteries were looked after by the store manager so I wasn't involved other than requesting a specific battery from him for a customer vehicle. However I was aware that "the battery man" would call roughly every month and check our battery stock, replenishing where necessary. It was also obvious that a certain number of batteries would be swapped out for new stock at each visit although I don't know how old they needed to be before being replaced by new stock. I must say that it was very rare for us to have a problem with our batteries, maybe because of the backup this chap gave us? I'm now wondering if Halfords have a similar arrangement with their suppliers. I tend to buy batteries from Halfords because I have one of their trade cards which gives me a very good discount and I drive past their door every time I'm going out to one of my boy's houses. I must call in and ask them how they manage their stock.

 

[GettinBetter]

I'm wondering if the energy used to recharge the battery, after a stop/start, is greater than the energy saved stopping it for 30 seconds (or however long the short delay is) ?

 

[Piccolo Nero e Bella]

I'm wondering if the energy used to recharge the battery, after a stop/start, is greater than the energy saved stopping it for 30 seconds (or however long the short delay is) ?

It's all about meeting emissions standards (on paper) - no matter if it doesn't work in the real world!

 

[GettinBetter]

It's all about meeting emissions standards (on paper) - no matter if it doesn't work in the real world!

...of course.

...for a moment, I'd forgotten about the narrative.

Good point.

 

[John202020]

Just cannot see the point of stopping the engine for 2 seconds say, I understand the principle so if you're stopped for 30+ seconds maybe, but with the ac or heater on it probably wouldn't cut in anyway

 

[GettinBetter]

Just cannot see the point of stopping the engine for 2 seconds say, I understand the principle so if you're stopped for 30+ seconds maybe, but with the ac or heater on it probably wouldn't cut in anyway

I agree, how do you know whether its going to be 2 seconds or 30 seconds. Anything under 30s is a extra cost, anything over is possibly a gain.

I think Piccollo nailed it, in his last comment. Suitably worded this 'feature' would confuse the ECO beaurocrats into just agreeing with it.

 

[jackdow98]

As an update to this post, stop start is now working! It kicked in after having a coolant leak repaired.

 

[Pugglt Auld Jock]

I have to start this by saying I'm genuinely concerned by climate change, emissions etc but Stop/start and the implications for vehicles with "normal" starter motors (the type that work by engaging with a ring gear on the flywheel) Turbo chargers (overheating oil because of interruption in oil supply) and other stuff causes me to punch the little button with the "deleted" A on it every time I start my engine. The long term implications for the longevity of these components should not be underestimated? So, Stop/start not working? sound like a bonus to me!

 

[GettinBetter]

As an update to this post, stop start is now working! It kicked in after having a coolant leak repaired.

Excellent news. Where exactly was the leak?

...... sound like a bonus to me!

You're probably right.

 

[Piccolo Nero e Bella]

Just cannot see the point of stopping the engine for 2 seconds say, I understand the principle so if you're stopped for 30+ seconds maybe, but with the ac or heater on it probably wouldn't cut in anyway

If the car's a manual at least the driver can anticipate how long he or she might be stopped and hold the brake and clutch, preventing the S/S from cutting the engine for short periods as I would normally do, especially if S/S were switched on. That would spare the extra wear and tear on components. I'm not sure how the system operates in the Dualogic - my wife's DL Pop didn't have S/S. Do you have to put the car in neutral first or does it stop the engine as soon as the car comes to a halt?

 

[jrkitching]

If the car's a manual at least the driver can anticipate how long he or she might be stopped and hold the brake and clutch, preventing the S/S from cutting the engine for short periods as I would normally do, especially if S/S were switched on. That would spare the extra wear and tear on components.

It's never a good idea to leave a stationary car with the engine running and the clutch depressed; it puts significant stress and wear on the clutch release bearing.

What I'd really like to see is the option to manually activate S/S by pressing a button on the steering wheel. Only the driver knows how long the car is likely to be stopped, and whether it's worth cutting the engine.