General OCS help

[nickdivers]

Hi,
After having the beeping red man for a year I decided to sort it out.
I have run the diagnostic software on the issue and cleared all the faults but one by cleaning the contacts. The last fault was with the OCS. I felt some lumps and bumps on the passenger seat so managed to remove the OCS using the guide from deckchair. The mat had become folded and som eof the contacts had interlaced. I flattened it out and plugged it back in, and it cleared the fault. The mat would pick a "passenger" whenever I put pressure on the mat. So I decided to glue some card to the mat in order to keep it flat. After the glue went off I checked it before I put everything back together. And there was a new fault.
32 - Passenger weight sensor - Unknown/Internal error - present - 5
Arghh I had it fixed for an hour!!!
Now the car thinks there is someone in the passenger seat no matter if there is pressure on the mat. Oddly though it says there is a passenger when the mat isn't even connected.

Has anyone had this problem? Is the fault still in the mat or is it somewhere else now?

 

[vladof]

What kind of glue did you use? Having another carpet on the mat may distribute the weight of the passenger unevenly, thus leading to a sensor failure.

Don't tell me it was superglue.

LE: I have lumps on my mat as well on one of the Stilos, maybe I should check that out. No errors though.

 

[nickdivers]

I used PVA so have since removed the card from the sensor mat. What's worrying is that the ECU is telling me that the passenger seat is occupied when the sensor isn't even plugged in.

 

[vladof]

Try removing the battery for 20 minutes or so with the OCS removed, that should reset it to stop showing the ghost of yourself is still on the seat.

Afterwards, start over. Plug the OCS, and if all is well, maybe even put back the mat if it doesn't show any errors.

 

[Argonought]

I'd strongly recommend reversing the OCS.

I did this just once and it sorted the problem completely.

It's not ideal (cables don't lay completely flat) but is a really cheap solution if you take care to carefully remove the cloth covering.

 

[nickdivers]

Ok, I just had the battery disconnected for an hour. no change. The car thinks there is a passenger present no matter what I do with the OCS. With it unplugged there are two faults, the one listed above, and one for the open circuit in the OCS. I plug it in and the open circuit disappears but the other remains. And still the amber man flashes and "airbag failure" appears. I think the fault is not in the OCS mat anymore but downstream somewhere else in the system. However I don't know where or even if there is more to the "weight sensor system".

 

[vladof]

Maybe you pulled something along the way on installing or removing the mat. Maybe Decks can lend a hand with the wiring.

I'm sorry mate I don't know what else to say.

 

[Deckchair5]

It still sounds like your OCS is broken.If you managed to straighten out the OCS and it temporarily cured the fault but then when you moved the mat again it retriggered the fault then the OCS broken

The car thinks there is a passenger present no matter what I do with the OCS.
Sorry, can you explain what you mean by that? What makes you think that the car thinks a passenger is present?

If the red airbag warning light on the dashboard is permanently on and you have airbag failure warning and FES is saying OCS internal fault then the OCS is broken

 

[nickdivers]

When I turn the key the amber light flashes to show that there is a passenger also with fiatecuscan plugged in there is a parameter for passenger present this returns "present". This all occurs whether the ocs is plugged in or not. The fault code that comes up now differs slightly from the first fault i had in that it has a different number in the last column (5). This error is marked as present again even without the ocs plugged in. I don't want to get a new ocs if all this is happening without the current ocs connected.

 

[Deckchair5]

The amber dashboard light flashes to show the airbag ECU is interrogating the OCS. It should do that at the first engine start and if a passenger moves in the seat otherwise it should stay off

If it stays on all the time then there is a fault with the OCS


This is how it should look- the two top right warning lights- (I'm just clearing a different airbag fault on the 2nd turning to MAR here- notice the top right airbag warning light stays off on 2nd turn on)

With FES meanings then it might be best to look on the FES forum. Some Stilos have OCS and some don't, probably because they proved to be so unreliable.

A lot of Fiat parts dept will accept a return with a handling fee if it proves not to be the part at fault but ask first about their Terms & Conditions before you order anything. You can, of course, just plug a new one in and see if it cures it without needing to totally fit it

 

[richydraper]

ive been scouring and registering on a shed load of different forums trying to sort my OCS issue... ive come up with this:-


takes some soldering but apparently its a 'working fix' im guessing it tells the ECU that the seat is always occupied so that it will deploy the airbag in the event of a crash.

the guy who PM'd me said:-

'the OCS pad must be cut and thrown away, the resistors are to be put directly on the electronics in the yelow rubber, the green lines are the cables'

i must admit this means NOTHING to me as i havent had the passenger seat apart to have a look YET but im assuming all these resistors act like the OCS mat when 'fully laden'.

HTH

 

[Argonought]

i must admit this means NOTHING to me as i havent had the passenger seat apart to have a look YET but im assuming all these resistors act like the OCS mat when 'fully laden'.

There's a whole stack of electronics on the connecting node of the mat (more complex than I expected).

Personally I'd put every effort into keeping it working as designed.

 

[richydraper]

if the mats were £50 id be in the same boat they're not so im happy looking for 'work arounds'

 

[nickdivers]

Decided to replace the mat. I called the Fiat dealership and got a quote of £240 for a new one. I thought that was a bit steep so using the wiring diagram and £6 of resistors from maplins the error has gone. I know it is not ideal and maybe to have it hard wired on for an adult but the difference in price makes it justifiable to me. From my earlier messages it appears that if there is a fault with the OCS the airbag ECU defaults to passenger present so the passenger airbag will deploy.

Thank you for all your help.

 

[richydraper]

did you manage to take any pictures of WIP and/or complete?

 

[richydraper]

RESURRECTION

i was messin around on ePER today for some plastic trims that i wanted as i thought id see how they compare to ebay... and found the following in the modifications section

Modification code 8809
Description REMOVED OCS SENSOR FROM PASSENGER SEAT
Activation VET 250210
Subcategory 55508

whats that all about can anyone elaborate?

 

[vladof]

Well one of the features of the facelift in 2004 was the OCS removal.

 

[Davren]

Well one of the features of the facelift in 2004 was the OCS removal.

It was removed before then Vlad, my car was built on 14/01/2003 and never had an OCS. It was only the very early cars that had them.

 

[richydraper]

i just got 'lucky' with mine...

lets see how 'lucky' i get with my MOT on friday

 

[vladof]

So Dave, does your airbag go off even if nobody is on the seat?

I had no idea they dropped the OCS so fast. Series 3 BMW's and above have this as well, they malfunction all the time so it's not just a FIAT fault.

I think they were better off trying to improve the OCS rather than removing it completely.

@Ricky: buy a decent emulator, put it in, and that's that. I'm surprised on how often you need to do the MOT. In Romania, it's once every 2 years.