Technical Engine keeps cutting out while driving

[Milly21]

Fiat 500 1.2L Lounge 2013 (63 plate). Engine keeps cutting out while driving. First occurred in April last year and has happened quite a few times since, although it's gone the longest of 8 months in between with no issues. Sometimes it will continue to drive, but other times it completely cuts out and won't turn over. Sometimes it'll start back up after leaving it off for a while, but it'll do it again after driving it for a bit. Other times it will just jolt, like it's cut out, but then come straight back on. No matter if it still drives or not, the engine and triangle with the exclamation mark lights come on. It says start stop's unavailable and to check engine. The error that comes up is all 4 of the ignition coils are circuit short to ground or open. The ignition coils were changed back in April and it then lasted 8 months, not including when the battery went (it was 11 years old so it was expected). There's apparently no issue with the ignition coils. The ECU was sent away to be refurbished, after which no errors were appearing when it broke down again. All of the wires have been checked and the connections cleaned. Any help will be much appreciated as the garage is getting a bit stumped on this too!

 

[Milly21]

Additional info: it did it last night but didn’t completely cut out, we didn’t need to pull over as it continued driving. Same lights and “start stop unavailable” “check engine”. Left it over night, lights were still on the next day. Turning over ok. Turned car on and off a couple of times, revved, turned on back wipers, opened and closed the boot and the lights went back off again. Don’t ask about the wipers and boot, my mum heard something about a possible lose connection in the boot causing this I think it’s just the turning on and off a few times that makes them disappear. Unfortunately I don’t have a code reader to know what comes up, although you’d think I would by now lol

 

[varesecrazy]

Additional info: it did it last night but didn’t completely cut out, we didn’t need to pull over as it continued driving. Same lights and “start stop unavailable” “check engine”. Left it over night, lights were still on the next day. Turning over ok. Turned car on and off a couple of times, revved, turned on back wipers, opened and closed the boot and the lights went back off again. Don’t ask about the wipers and boot, my mum heard something about a possible lose connection in the boot causing this I think it’s just the turning on and off a few times that makes them disappear. Unfortunately I don’t have a code reader to know what comes up, although you’d think I would by now lol

Hi,

The 500 is prone to the wires at the tailgate breaking ( opening and closing tailgate thousands of times stresses them)

However...

A more general issue is a chunky cable next to the engine

It links the Battery to the Chassis and Engine

Basically it's not well sealed and Roadsalt and age make the copper inside it turn to a green paste


This means it struggles to reliably pass electrical current

It's a cheap and simple item to replace.?
Garages cleanup the ends.. Of little use if the middle is falling apart


That should help Howard to be great again

 

[Greasytrucker]

If you said opening and closing the boot made the lights go off then I’d start by checking the wiring inside the rubber casing that you can see when you open the hatch (boot) as this can cause all sorts of problems and is a common failure point

 

[Greasytrucker]

Hi,

The 500 is prone to the wires at the tailgate breaking ( opening and closing tailgate thousands of times stresses them)

However.

A more general issue I'd a chunky cable next to the engine

It links the Battery to the Chassis and Engine

Basically it's not well sealed and Roadsalt and age make the copper inside it turn to a green paste


This means it struggles to reliably pass electrical current

It's a cheap and simple item to replace.?
Garages cleanup the ends.. Of little use if the middle is falling apart


That should help Howard to be great again

They say great minds think alike!

 

[varesecrazy]

For the hatch wires SEARCH

"MAYBELLINE" on here

 

[steveras57]

Check the hatch wires first if any broken or damaged insulation thats the place to start!.
You can check the main earth by temporarily fitting a jump lead cable between the battery neg terminal and a good earth point in the engine bay(chassis bolt or the like make sure its unpainted!) if things improve then replace the cable under the battery tray ! many members have also run a second cable from the battery to the chassis as per the jumper cable quote as the stock set up isn't very good!

 

[Milly21]

If you said opening and closing the boot made the lights go off then I’d start by checking the wiring inside the rubber casing that you can see when you open the hatch (boot) as this can cause all sorts of problems and is a common failure point

Yes, my Mum was told about this and said to give it a try however I wouldn’t say it was connected as they didn’t immediately come off after doing that. Usually they come off after turning the car off and on again a few times I will be bringing this common issue up to the garage though, just to look into it a bit more, thank you

 

[Milly21]

Hi,

The 500 is prone to the wires at the tailgate breaking ( opening and closing tailgate thousands of times stresses them)

However...

A more general issue is a chunky cable next to the engine

It links the Battery to the Chassis and Engine

Basically it's not well sealed and Roadsalt and age make the copper inside it turn to a green paste


This means it struggles to reliably pass electrical current

It's a cheap and simple item to replace.?
Garages cleanup the ends.. Of little use if the middle is falling apart


That should help Howard to be great again

i’ll definitely get them to check that cable a bit deeper if they haven’t already. i’m being told a lot about the tailgate/hatch wiring, could that cause the engine to cut out? i feel like the issue is definitely electrical/wiring of some sort

 

[Milly21]

Hi,

The 500 is prone to the wires at the tailgate breaking ( opening and closing tailgate thousands of times stresses them)

However...

A more general issue is a chunky cable next to the engine

It links the Battery to the Chassis and Engine

Basically it's not well sealed and Roadsalt and age make the copper inside it turn to a green paste


This means it struggles to reliably pass electrical current

It's a cheap and simple item to replace.?
Garages cleanup the ends.. Of little use if the middle is falling apart


That should help Howard to be great again

Is there anyway you could show me what wire this is?

 

[steveras57]

Is there anyway you could show me what wire this is?

Could be any of around twenty in there! SLOWLY pull back the rubber boot from the tailgate (right) side if theres anything wrong you should see it straight away!

 

[Milly21]

Could be any of around twenty in there! SLOWLY pull back the rubber boot from the tailgate (right) side if theres anything wrong you should see it straight away!

ah i meant the chunky one

 

[Mike1alike]

It's the larger one that goes from battery terminal (-) to body and further to gearbox.
As for your problem, don't disregard the crankshaft positioning sensor as it could be the culprit. It does have the habit of going partially off, works ok while cold and doesn't work when gets really heated and that causes the engine to stop because ECU is "seeing" (by the faulty sensor signal) that crankshaft isn't revolving so it stops the fuel injection. Either test the sensor cold and hot either just replace it with a new one.
Here is a video on how to test it.

 

[Mike1alike]

Here is a video on how to test it.

Besides what's in the video (and it's the crankshaft sensor you need to test) it's important that after you read voltage on sensor when you put a metal part near its tip to test it while it's hot. You can easily use a hair dryer to heat it up, couple of minutes on it and it gets hot, then you read the voltage again. If there's no voltage when the sensor is hot it means that the sensor it's damaged and needs replacement.

 

[Milly21]

Besides what's in the video (and it's the crankshaft sensor you need to test) it's important that after you read voltage on sensor when you put a metal part near its tip to test it while it's hot. You can easily use a hair dryer to heat it up, couple of minutes on it and it gets hot, then you read the voltage again. If there's no voltage when the sensor is hot it means that the sensor it's damaged and needs replacement.

A couple of people have said about the crankshaft sensor, the codes showing up are the ignition coils (despite them being replaced multiple times) apparently there’s no issues surrounding them. Would that sensor affect those codes coming up?

 

[varesecrazy]

For the hatch wires SEARCH

"MAYBELLINE" on here

This explains all the hatch wiring..

 

[Mike1alike]

Would that sensor affect those codes coming up?

I don't think it would, but I don't think that it would be impossible to throw them.
For the wiring problems though, listen to Charlie and search for that 'MAYBELLINE'.

 

[Ralf S.]

A couple of people have said about the crankshaft sensor, the codes showing up are the ignition coils (despite them being replaced multiple times) apparently there’s no issues surrounding them. Would that sensor affect those codes coming up?

Crank sensor is possible.. but no, a dead crank sensor gives all the symptoms of the ignition being switched off. You get no sparks and no fuel .. the ECU doesn't know it has to provide those, so it doesn't know anything is wrong.

A failed sensor usually comes back after it cools down... so if your car drives for a while, then cuts out and immediately re-starts then it's unlikely to be the sensor. That would need several minutes... although "failure" behaviour is by definition unpredictable.

It's more likely (and free to test) to be the battery earth strap. If you have a battery jump lead, attach it to the battery negative post and connect the other end to the engine lifting hook or anywhere metal where it can get a good grip. The car should start working again immediately.


Ralf S.

 

[Milly21]

Crank sensor is possible.. but no, a dead crank sensor gives all the symptoms of the ignition being switched off. You get no sparks and no fuel .. the ECU doesn't know it has to provide those, so it doesn't know anything is wrong.

A failed sensor usually comes back after it cools down... so if your car drives for a while, then cuts out and immediately re-starts then it's unlikely to be the sensor. That would need several minutes... although "failure" behaviour is by definition unpredictable.

It's more likely (and free to test) to be the battery earth strap. If you have a battery jump lead, attach it to the battery negative post and connect the other end to the engine lifting hook or anywhere metal where it can get a good grip. The car should start working again immediately.


Ralf S.

The issue is that the car is currently working. It cuts out and sometimes stays off for a while but it always comes back on. How would I go about testing it while it’s on?

 

[Ralf S.]

Crank sensors break down with internal resistance when they're hot.. so they're not easy to diagnose... you'd need to leap out of the car, dismantle enough to get to the sensor and then test the resistance. Post 14 up there ^ has a video... I haven't watched it.. but I guess it shows how to test the sensor.

If it was me, I'd go to Halfords, buy a long battery earth lead and then connect it up from the battery earth to a point on top of the gearbox.. plenty of bolts you can use around there. If that prevents the problem occurring then you discovered the problem and can rig up a neater repair. If you still have problems then it's not the earth strap... so then you can look at the crank sensor. Earth strap is the easier to eliminate, so try that first. The £6 can save you a lot of time/effort.


Ralf S.