Technical Bonnet open error message [earth a BC pin]

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Technical Bonnet open error message [earth a BC pin]

frciy86

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Hi!

I have a problem. My 02 fiat stilo 1.6 shows me open bonnet message after startup.The interesting thing is that I never had a factory fitted alarm, The release mechanism has no switch in it it is a plain simple bonnet catch.I never had this message strangely it popped up yesterday and since than it keep buzzing that the bonnet is open.I tried disconnecting the battery, tried to find the error with FES but no.
It seems that it just popped up from nowhere after the battery run a little flat after a cold night..
Can anyone please help me..I'm out of ideas...tried the search option too but is seems only 2-3 guy had the same problem and they all had factory alarms fitted..
 
May be it did have a bonnet switch, once upon a time, but it has since been removed and the wires leading to the bonnet switch connected together? If they are now a little corroded and not properly connected together anymore it may be the reason your now getting an error? Just a thought?
 
I know that in one of the other cases (an Abarth) the issue was never resolved despite an intensive investigation. There was evidence the loom had been cut back effectively as far as the body computer. In that case too the problem started spontaneously.

If you're absolutely certain your Stilo was never fitted with an Alarm then this is starting to look rather worrying :(

What's the rest of the spec like on your motor as a matter of interest?
 
This was the first time the "open bonnet" message popped up...My car is a really early make it has no A/C and it's a really basic model so I don't really think that it has/had an alarm fitted ever...(it has no remote control key , and it's not possible to program one to the BC)...so does this mean that I'm stuck with this error message ..oh and does that mean that I must prepare for more to come..??
 
...so does this mean that I'm stuck with this error message ..
This looks like it might be the case as I don't think anyone has yet found a logical cause. It should be measuring a sensor (i.e a switch) and therefore very easy to resolve but that hasn't been so in all the cases I'm aware of.

If it affects your Stilo then it might affect ALL Stilos!

It's also very strange as some alarm functions would seem to be embedded within the body computer, on all Stilos, after all. I came to the opposite conclusion when experimenting with the oem alarm some years back :chin:

I'd guess some corrosion is taking place on the body computer to cause this so a replacement should therefore resolve it.

Can you explain exactly how & when the message is displayed?
 
Yes...!
it happened after a colder night, when my car wasn't in the garage...it seems that the battery lost a little bit of charge...and I managed to slam the boot and the boot open message popped up...so I searched the forum and found out that the problem is with the micros switch..I repaired the micros switch and the boot open message didn't pop up anymore but then I go the bonnet open message...tried to set the alarm code via FES (read on one forum that if U set the alarm function the 0 then the body computer inhibit this function, the alarm function) but that didn't do the trick...investigated the bonnet catch but nothing...no wire nothing...the bonnet open message just popped up without any sign before.
So what can I do..?Oh and last weekend I changed the brake pads but I do think it has anything to do with that error mesage
 
The bonnet switch (if you had one) is I10 on the wiring diagram and it connects an earth signal to pin 24 of connector B on the Body Computer M1 when the bonnet is closed.

You could try connecting an earth wire directly to pin 24 of connector B on the BC. If there is already a wire connected to pin 24 it should be light blue/dark blue, shown as AL on the diagram.

According to the workshop manual, connector B on the BC is blue but sometimes the connector colours are shown incorrectly.
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The bonnet switch (if you had one) is I10 on the wiring diagram and it connects an earth signal to pin 24 of connector B on the Body Computer M1 when the bonnet is closed.

You could try connecting an earth wire directly to pin 24 of connector B on the BC. If there is already a wire connected to pin 24 it should be light blue/dark blue, shown as AL on the diagram.

According to the workshop manual, connector B on the BC is blue but sometimes tte connector colours are shown incorrectly.
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So if someone had the bonnet micro switch they could bypass it by doing as you say?
 
So if someone had the bonnet micro switch they could bypass it by doing as you say?

Yes.. but if someone had the switch fitted they could earth the signal wire at the switch to bypass it rather than at the BC. That's what's been done on my car because a bonnet catch without the switch has been fitted at some time.

Earthing pin 24 of connector B is only a suggestion of something to try because we haven't found a cure for this problem yet. It could be that for cars without the alarm, pin 24 isn't connected to anything inside the BC so earthing pin 24 may have no effect at all.
 
So if I earth pin 24 on connector B that could solve my problem...but if I don't have anything connected to that pin than this solution would not work fro me..?Ok so Friday or this weekend I will try this solution..:D I hope it works because if randomly other error messages will pop up than I have a seriuos problem with my BC :((
 
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Thank You DAVREN!!!!!!!:worship:
You are the best...earthing pin 24 solved my bonnet open problem..wow that was a quick and easy fix...:D.
The pins on connector B are numbered so you can easily identify pin 24
You just need do take out the connector from the harnest clip , in my case the pin was not wired so i just put a wire in the connector body where pin 24 is and earthed the other end.
Quick and easy fix so you don't need to sell your stilo after all if u have the stupid bonnet open message popping up..(y)
Next time will take some pics to show you how I've done it..
 
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Hopefully, that's another Stilo quirk resolved then. If the external earth wire resolved the problem, it would suggest that the pull up resistor inside the BC wasn't doing it's job. Fiat dealer would have said you need a new BC.

@ frciy86 ...Out of interest, was connector B blue?
 
hopefully this weekend I will have some time to take some pics..the rest is really easy..(y)
@Davren yes the B connector was blue, the other one was white.In reality there are 2 connector hold together by a blue colored plastic body with a retain clip (this connects in the body comp) on it and inside this is the connector B , blue colored and the other white connector.
 
SOLVED in other WAY:

0) Maybe this step is not necessary but: set valid alarm type in BC ( mine is 0 - no alarm ) - you need a ELM & ECUSCAN.

Turn the key to the OFF position and close all doors ( leave the bonnet open only ).
[ for safety leave some windows open ;) or take the second key to the pocket ]

1) Take the PLUS wire out form the akku ( leave the EARTH/ZERO connected to akku ) [ car died :) ]
2) Turn the key on to the MAR position [ car is still dead :) ] and close door.
3) Put the PLUS wire back to the akku [ car is back to business, some sparks can appear when connecting the wire ].

And problem should be SOLVED !

About DOOR CLOSING. I don't know if it's necessary but some errors can be cancelled by turn key to the MAR on with all doors closed ( hood, etc ).
( I cancelled Fuel Filter error in this way , cause I forgot to plug the wire back to the filter and have turned the engine on)
 
SOLVED in other WAY:

0) Maybe this step is not necessary but: set valid alarm type in BC ( mine is 0 - no alarm ) - you need a ELM & ECUSCAN.

Turn the key to the OFF position and close all doors ( leave the bonnet open only ).
[ for safety leave some windows open ;) or take the second key to the pocket ]

1) Take the PLUS wire out form the akku ( leave the EARTH/ZERO connected to akku ) [ car died :) ]
2) Turn the key on to the MAR position [ car is still dead :) ] and close door.
3) Put the PLUS wire back to the akku [ car is back to business, some sparks can appear when connecting the wire ].

And problem should be SOLVED !

About DOOR CLOSING. I don't know if it's necessary but some errors can be cancelled by turn key to the MAR on with all doors closed ( hood, etc ).
( I cancelled Fuel Filter error in this way , cause I forgot to plug the wire back to the filter and have turned the engine on)

For the record, this method worked for me (y)
 
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