Technical Start-Stop system operation

[Tropicalmike]

The start-stop system isn't working on our 69 plate twin air 500 and I put it down to a slightly weak battery. But I swapped it over to our other twin air in the family ( start stop had worked intermittently on that one ) . The start stop started to work in the 2nd one straight away consistently so I concluded the battery was definitely OK . So I started to look into it a bit further for other possible reasons. We quite like it working when driving in town at busy times with many traffic lights and saves a bit of fuel (supposedly!)

Checks and tests made :-

• I had also checked the battery with an electronic tester and after a good two hour drive and it showed 97% state or health ( SOH) and 98% state of charge (SOC) and CCA at 600 A correct too.
• I disconnected and inspected and cleaned all battery terminals and earth strap on body and gear box , they were all good, no corrosion
• I have had a good read on the FIAT e-learn website ( copy attached of 20 page description ) I then and hooked up my multiECUscan. (MES) The e-learn gives a good description of what inputs effect the Start-Stop. IE . Clutch pedal released, gear in neutral, disable push button and Brake servo pressure switch and battery monitor sensor , The clutch. gear neutral and servo pressure switches all could be seen to work but there is no parameter for the battery monitor in MES. The parameter for start stop disable did not change when I pushed or held the button. However, the yellow disable light shows in the instrument cluster so I am pretty sure that signal works
• I checked the fuse that feeds the battery sensor F87 and it was OK.
• I put my multimeter on the wiring connector of the IBS and the +ve 12 V was present and there was a resistance between the 2 pins on the monitor. I also checked the battery voltage when charging with engine running, up to 14v present at times.
• I then unplugged the Intelligent battery sensor (IBS) . This generated a fault code U1411-87 in MES and the yellow fault light triangle on instrument panel. This not surprisingly is the fault for loss of signal from intelligent battery sensor . I plugged it back in and cleared the fault , The wiring diagram shows the other wire from the IBS goes into the body computer as a LIN signal , as does the other switches already mentioned . The e-learn description says the info from the body unit BCM communicates with the engine ECU via the Canbus where the start-stop is actually controlled
• I swapped the Intelligent battery sensors over between the two cars , both worked in the 2nd car.
• I removed the start-stop system relay T10 and tested the relay on the bench , all OK . With this relay missing the car could still be started with the key and it brought up the DTC P0512-13 starter motor signal ( plausability ) . With the relay refitted I deliberately stalled the car . I got the message to put my foot on the clutch and the engine restarted automatically so I am sure the circuit for re-start is OK. It is just the auto stop part is not working.
• When monitoring the 3 parameters in MES for start stop ( see attached ) this is what I get when the engine is warm and the car is stopped with clutch released and in neutral. It just doesn't stop . On the other car with the same parameters the car does stop. If I open the drivers door or undo the drivers seatbelt or push the disable button I can change the status to "off" and temporary deactivation to "disabled" . This corresponds to the description in e-learn for things that disable the start stop from the BCM. I also tried the wipers at high speed and heated rear window but this had no effect. Nor with the working Start stop on the other car. So clearly it does not follow the e-learn entirely. I am assuming parameter " start stop request" as the signal from the BCM blocking or not the start stop . As the IBS is also connected to the BCM I also think the request would be "off " if the battery is at a low charge or getting old
• I have checked all the parameters listed that are connected to the ECM involved in allowing start stop and they check out and can be seen to change as appropriate. None are showing a fault .
• When I release the clutch when stopped in neutral the engine revs surge slightly from 820 to about +30 revs for a moment , just when it should stop. Not sure if this is significant or not.

I would appreciate it if someone has time to review what I have done so far and see if I missed something or if anyone has any other ideas , cheers

I appreciate that in the big picture that no start stop isn't the end of the world and I know that some hate it and leave it switched off . But I would like to get it working if I possibly can so would like any technical advise available, Thanks in advance

 

[GettinBetter]

I been here...
Just a couple of suggestions.

1. Test your battery a couple if hours after you've turned it off, not straight after a run.

2. Connect the negative lead of a set of jump leads from the negative terminal to the far side of the engine ( an nice clean point). Try your Stop/Start button.

Posts results if you would be so kind.

BTW, did you know that MES 5.3 is available now? Its a simple update.

 

[Tropicalmike]

I been here...
Just a couple of suggestions.

1. Test your battery a couple if hours after you've turned it off, not straight after a run.

2. Connect the negative lead of a set of jump leads from the negative terminal to the far side of the engine ( an nice clean point). Try your Stop/Start button.

Posts results if you would be so kind.

BTW, did you know that MES 5.3 is available now? Its a simple update.

Hi, Thanks for the prompt reply

I tested the battery before it was driven today, 96% SOH and 91% SOC . sounds about right loosing 7% overnight , and it was bloody cold this morning

Not sure exactly where you are suggesting to connect a jump lead at the battery negative ?. Direct on the battery terminal or on the Quick release terminal that has the IBS between it and the main negative battery terminal. If the former, it effectively bypasses the IBS current monitor part . The other way is just an extra bond from the engine . The IBS wont detect current and I think it will generate an error and probably block start stop from working ( for a different reason)

Do you mean try to push the start-stop disable button or start/stop the car with the key ? what are you expecting I will see ? The disable button has always brought up the yellow light "SS disabled" symbol . I don't think I can or want to drive with a jump lead dangling around under the bonnet to check if start-stop kicks in.

I also checked our other 500 today lifting the clutch in neutral does not cause a small surge in speed , I did it before the car was warm to make sure it didn't cut out with start stop

Yeah, I did see MES 5.3 was available , will try and download the upgrade . Thanks for the reminder

cheers

 

[A3jeroen]

I woud check (or change over) the clutch pedal sensor).

gr J

 

[GettinBetter]

...The IBS wont detect current and I think it will generate an error and probably block start stop from working ( for a different reason)..

Ok, that's fine. You obviously know what you're doing, I'll leave you to it.

 

[Tropicalmike]

I woud check (or change over) the clutch pedal sensor).

gr J

I will have a close look . I think I have to change the clutch master cylinder now as the pedal has stuck down a couple of times in recent weeks . so I will be crawling around in the footwell. It looks like it is all in the right side footwell . I note your posts in my other thread when I tried to do the clutch pedal alignment learning and had the issue with the stating blocked

 

[Baglady1990]

Anyone else think that drastic temperature change affects the S/S ? My only explanation for mine suddenly stopping.. then coming back out the blue a few weeks later … I know it’s notorious and yes I hate it! But I also like to know it works

 

[Piccolo Nero e Bella]

Anyone else think that drastic temperature change affects the S/S ? My only explanation for mine suddenly stopping.. then coming back out the blue a few weeks later … I know it’s notorious and yes I hate it! But I also like to know it works

I have exactly the same attitude toward my S/S but you've reminded me I haven't switched it on for some time! Do I turn it on next trip and risk finding it doesn't work or leave it off and carry on in blissful ignorance?

Never noticed any problems with temp change on the S/S but (unrelated) my car doesn't like very hot weather (35C+) and will splutter if you try to take off too quickly for its liking - fine once it's rolling.

 

[Baglady1990]

I have exactly the same attitude toward my S/S but you've reminded me I haven't switched it on for some time! Do I turn it on next trip and risk finding it doesn't work or leave it off and carry on in blissful ignorance?

Never noticed any problems with temp change on the S/S but (unrelated) my car doesn't like very hot weather (35C+) and will splutter if you try to take off too quickly for its liking - fine once it's rolling.

Don’t rub it in!! We just had a frozen spell snow & ice … now it’s wet n windy!

 

[Tropicalmike]

In cold temperatures a lead acid battery cannot deliver the same level of high current. That is why there are generally more problems starting engines in cold snaps especially for older batteries or at a low level of charge. The Fiat e-learn does mention temperatures blocking start-stop system. But it says engine temp.outside the range 40 - 100 deg.C and battery below -23 deg. C. But to be honest I dont know if it those are entirely accurate as it says wipers at high speed and heated rear window will also block s/s but it doesnt in my experience of investigating why my one is not working .

 

[Baglady1990]

In cold temperatures a lead acid battery cannot deliver the same level of high current. That is why there are generally more problems starting engines in cold snaps especially for older batteries or at a low level of charge. The Fiat e-learn does mention temperatures blocking start-stop system. But it says engine temp.outside the range 40 - 100 deg.C and battery below -23 deg. C. But to be honest I dont know if it those are entirely accurate as it says wipers at high speed and heated rear window will also block s/s but it doesnt in my experience of investigating why my one is not working .

Mine never worked properly until I bought a new battery.. I bought a Halfords SS battery first but soon enough SS stopped working… battery was fine but I replaced with a varta and 2 years later SS works faultlessly.. but with intermittent periods of disappearing mainly I’ve noticed when temperatures plummet
I keep on top of battery charging.. just to keep it healthy and I periodically clean up the contacts and SS sensor with metal polish
Personally I just think it’s a system

 

[Tropicalmike]

Agree, The system is too clever. The e-learn says the intelligent battery sensor (IBS) has a temperature sensor in it. I wonder if there is some wind chill factor under the bonnet or if the SOH or SOC value is somehow getting lowered/distorted when the ambient temp is low. I am going to check into this clutch pedal sensor once the weather improves. I feel pretty confident the S/S block is from the ECM and not the BCM /IBS from what I can see on MES parameters for start stop on my TA engine.

 

[The Panda Nut]

I have exactly the same attitude toward my S/S but you've reminded me I haven't switched it on for some time! Do I turn it on next trip and risk finding it doesn't work or leave it off and carry on in blissful ignorance?

Never noticed any problems with temp change on the S/S but (unrelated) my car doesn't like very hot weather (35C+) and will splutter if you try to take off too quickly for its liking - fine once it's rolling.

Blissful ignorance. Maybe it gives a lkittle prewarning of the battery failing. Both our 1.2's suffered instant terminal battery failure which is a pain in the rear en.

 

[The Panda Nut]

Mine never worked properly until I bought a new battery.. I bought a Halfords SS battery first but soon enough SS stopped working… battery was fine but I replaced with a varta and 2 years later SS works faultlessly.. but with intermittent periods of disappearing mainly I’ve noticed when temperatures plummet
I keep on top of battery charging.. just to keep it healthy and I periodically clean up the contacts and SS sensor with metal polish
Personally I just think it’s a system

Mine still works its 5.5 years old now, but it has got slightly tempremental in the last 3 months. Charginhg the battery brings it back and if the car is used it works after 2 weeks standing its hit and miss but the battery still holds 12.6v after periods of standing so maybe this system just wants to see things at 100%, much like the VW Golf TDI and its limp home for a 99.8% of standard signal. ENgineers need to think of building in a fraction more slack for ageing and wear and tear I think. Who's going to buy a £150 battery before its actually needed?

Oh that would be me... I seem to have a brand new Exide Panda battery on the shelf right now. Unfortunately not for the stop start car. ALso have 3 rear wiper arms / blades, 2 sets of front wipers 3 oil filters,1 pollen filter, a coil pack, 2 sets TA plugs, 4 sets 1.2 plugs. two front exhaust to gearbox brackets, 1 brake pads etc etc I wish I could control this. Its far worse with tools I once counted 5 13mm combi spnners then theres 3 mole grips about 50 hammers, 5 hacksaws. remnants of at least 5 socket sets 4 or 5 hydraulic jacks. The worlds shortage of scrap iron and steel will be solved for 5 years when I croak

 

[Piccolo Nero e Bella]

Personally I just think it’s a system

Absolutely! Even if it works perfectly it's no bloody use! I'm just grateful my car was built when the on/off switch was just that - permanently on or off. The baleful orange glow of the 'Eye of Sauron' on the dash doesn't even register any more...

 

[Piccolo Nero e Bella]

Blissful ignorance. Maybe it gives a lkittle prewarning of the battery failing. Both our 1.2's suffered instant terminal battery failure which is a pain in the rear en.

I'll be taking mine out on Thursday and, if I remember (no guarantee these days!!), will test the S/S for that trip. The EFB is now over seven years old but it spends its idle time, often a week at a time, connected to the CTek charger. And anyway, as Baglady hints, our climate is much friendlier toward batteries.

 

[Tropicalmike]

I have now succeeded in getting the start-stop to work .

I had downloaded the updated version MES 5.3 a few days ago and had a look in simulation mode . For the twin air engine there was now a new different version showing for the engine "Magneti Morelli IAW 8GSW CF6D injection (0.9) " In this version there are some differences in parameters and now includes "IBS battery charge status" in % . So quite useful in checking on start stop diagnosis. My engine had used the version 8GSW CF6/EOBD to connect in MES before. But when I connected today it now says I should connect with the new CF6D version. So good news , I can see the new parameters including battery charge status.

The car had been driven for about 40 mins today and the IBS battery charge status said 99% when I connected. The status on the 3 start- stop parameters also showed , "on", "on" and "not present " when I stopped after driving and put car in neutral and clutch released. But it didn't stop .

So I took a chance and carried out the "clutch pedal learning" adjustment again ( if you read my disaster thread when I couldn't restart the engine after doing this adjustment ) . I then checked the pedal position %age reading whilst moving the pedal, There was no change it went from 1.5% to 99% from released to fully pushed and the two switches for clutch pedal position also showed correct . So I moved the car again with the MES connected and tried it again . The Start stop still didn't work,

I then tried the "neutral signal learn" adjustment again. The result in parameters stayed the same . It just says "learned". The gear position stays in neutral/none the whole time unless reverse is selected .

I then moved the car again and low and behold when stopping the car the start-stop kicked in and it stopped. So I drove the car around the block and tried it 4 more times and it worked every time . Not really sure what I did different , if anything, but it seems doing the neutral signal learn was the key.
The notes in the MES adjustments does say the clutch pedal learning and neutral signal learning are critical to the start stop . it would be nice if MES could tell you if detecting/showing neutral.

After sitting on my drive with lights on and engine stopped for quite a while this evening the battery IBS reading dropped to 85% . According the e-learn going below 75% State of charge will also block start stop .

So in summary , for anyone trying to get Start stop to work . Read the ""start stop description" attached to the first post of this thread and once you are sure the battery is OK then carry out the clutch signal and neutral signal learn , possibly twice .

 

[Baglady1990]

I have now succeeded in getting the start-stop to work .

I had downloaded the updated version MES 5.3 a few days ago and had a look in simulation mode . For the twin air engine there was now a new different version showing for the engine "Magneti Morelli IAW 8GSW CF6D injection (0.9) " In this version there are some differences in parameters and now includes "IBS battery charge status" in % . So quite useful in checking on start stop diagnosis. My engine had used the version 8GSW CF6/EOBD to connect in MES before. But when I connected today it now says I should connect with the new CF6D version. So good news , I can see the new parameters including battery charge status.

The car had been driven for about 40 mins today and the IBS battery charge status said 99% when I connected. The status on the 3 start- stop parameters also showed , "on", "on" and "not present " when I stopped after driving and put car in neutral and clutch released. But it didn't stop .

So I took a chance and carried out the "clutch pedal learning" adjustment again ( if you read my disaster thread when I couldn't restart the engine after doing this adjustment ) . I then checked the pedal position %age reading whilst moving the pedal, There was no change it went from 1.5% to 99% from released to fully pushed and the two switches for clutch pedal position also showed correct . So I moved the car again with the MES connected and tried it again . The Start stop still didn't work,

I then tried the "neutral signal learn" adjustment again. The result in parameters stayed the same . It just says "learned". The gear position stays in neutral/none the whole time unless reverse is selected .

I then moved the car again and low and behold when stopping the car the start-stop kicked in and it stopped. So I drove the car around the block and tried it 4 more times and it worked every time . Not really sure what I did different , if anything, but it seems doing the neutral signal learn was the key.
The notes in the MES adjustments does say the clutch pedal learning and neutral signal learning are critical to the start stop . it would be nice if MES could tell you if detecting/showing neutral.

After sitting on my drive with lights on and engine stopped for quite a while this evening the battery IBS reading dropped to 85% . According the e-learn going below 75% State of charge will also block start stop .

So in summary , for anyone trying to get Start stop to work . Read the ""start stop description" attached to the first post of this thread and once you are sure the battery is OK then carry out the clutch signal and neutral signal learn , possibly twice .

My SS has disappeared again after coming back and working flawlessly… despite doing 40 miles a day and my battery is in tip top condition.. might give this a go!! I’d be interested how long your SS works for without stopping again if it even stops …

 

[Tropicalmike]

Not sure how old your engine is . Just be wary with the clutch position learning especially if the clutch is required to be depressed to do the first start with the key. See my thread

Start-Stop system disaster - MultiECUscan expert users help please! | FIAT 500 (2007+)

Hi , I used MultiECUscan (MES) to assist me in trying to get the Start-Stop working on my wife's 500S Twinair (85PS) . This after I had eliminated a battery and battery sensor issue . It seemed to point to some thing with the clutch released or the gear in neutral signal. I had read the...

www.fiatforum.com

 

[Baglady1990]

Not sure how old your engine is . Just be wary with the clutch position learning especially if the clutch is required to be depressed to do the first start with the key. See my thread

Start-Stop system disaster - MultiECUscan expert users help please! | FIAT 500 (2007+)

Hi , I used MultiECUscan (MES) to assist me in trying to get the Start-Stop working on my wife's 500S Twinair (85PS) . This after I had eliminated a battery and battery sensor issue . It seemed to point to some thing with the clutch released or the gear in neutral signal. I had read the...

www.fiatforum.com

It’s a 2011 1.2 no the clutch doesn’t need to be pressed but thank you I’ll read the thread