Technical Stop Start Woes - 500C

[phurst221174]

Hi all, new to the forum and have recently bought a 2012 500c for my daughter.

I've started to get stop start issues so was wondering if anyone can give ideas to look at.

Issues:

Get Hill Decent & Stop Start not available + ASR disconnected warnings.

So far I've done / tested the following:

Clutch control switch (the one in passenger foot well)

Battery voltages are 12..4V engine & electrics off, drops to 11.9V when key turned to first position then rises to 13+V when engine started.

I'm an electronics engineer by trade so happy with following circuit diagrams / checking wiring out but not really done anything mechanical wise with cars.

Any pointers would be appreciated.

Paul.

 

[varesecrazy]

Hi Paul, and Daughter

Is this a Cabrio..?

 

[phurst221174]

Hi, yes it is.

She was over the moon with the fact it was a soft top and even more so that it's the same colour as her prom dress.

 

[varesecrazy]

A VERY common 500 issue is broken/ fraying wires in the Rear Hatch..



I believe the cabrio is immune to this.. But worth looking around there

 

[Derbyfella]

A VERY common 500 issue is broken/ fraying wires in the Rear Hatch..



I believe the cabrio is immune to this.. But worth looking around there

Hi
we had one
and no, it can suffer the same issue with the wiring - although there are only 7 wires if memory serves me correct and obviously no water pipe.


Main earth strap in decent condition?

 

[phurst221174]

Am off on Thursday so will have a good look around during the daylight.

A few things I forgot to mention originally which may be significant

When I start the car initially the ASR switch works fine, ie I can select and deselect ASR with no issues

Additionally I can also switch on and off the stop start system with no issues

The warnings all start as soon as I press the brake pedal for the first time.

 

[varesecrazy]

After a check over for obvious wiring damage..

It may be worthwhile getting the related fault codes read..

Could save a lot of grief
1, the full code should point to a specific issue
2, entering said full code into the forums excellent SEARCH..
should find 500 model specific threads where you may well find the story and fix

 

[Derbyfella]

simple as brake pedal switch?

 

[varesecrazy]

simple as brake pedal switch?

I was thinking that had been covered..
But it was the Clutch switch..

 

[PuntoHowTo]

It’s worth checking the battery condition monitor on the terminals (I forget which but want to say negative) there is a wire comes off the battery monitor that can often break.

My instinct suggest if it’s when you press the brakes then it might be rear light related. If there is a fault on the reverse light circuit with fiats then it can error out the stability control system (the car uses the reverse light circuit to turn off stability control when going backwards intentionally)

A faulty earth on the rear lights can cause a reverse current thought the other lights in the cluster, which will confuse the body computer.

So check the wiring as discussed above as it’s very common on all fiats.

Then make sure you have a ready good earth to all the back lights.

I’d actually recommend putting in a second ground for the back lights on any fiat.

 

[phurst221174]

I was thinking that had been covered..
But it was the Clutch switch..

I'm getting confusing info from looking on Google

The switch I checked / replaced is this one (in the passengers footwell)

I've also seen people mention about another switch, is that this one?

 

[PuntoHowTo]

Check the wiring in and around the boot first.