Intermitant AIRBAG light / car no crank

[adrianw]

Hi,

While on holiday in Ireland recently my 2002 Boxster S started a new habit of not cranking and tossing airbag errors.

At first it was just on the first turn of the they - 2nd time it started.

The pattern that emerged is that I got air bag failure warning after a few seconds of switching the ignition on.

This gradually got worse, requiring ignition on / off half a dozen times – standing on one foot with a finger in the ear etc etc.

We got home though - but not a great feeling when you have a ferry to catch, fuel to add etc.

I hooked up the Durametric and it tells me that when the fault is active it cannot locate the airbag module.
On the odd occasion when the car passes its airbag tests I can see these errors:

AirBag Error 3 Supply voltage
I32 Alarm system: Error 25 W lead (sometimes not present)

I have checked and swapped the 7.5 Amp Row E fuse 1 – it is fine. (All fuses give tone in the continuity tests I did)

The airbag module has 5670 hours on it – are capacitors an issue?

Any ideas for me to try -any one else seen this intermitant issue?

I am about to take apart the centre console to check that nothing has come loose.

Cheers

Adrian


I looked at this: Fuse is fine.
https://986forum.com/forums/boxster-general-discussions/62092-airbag-light-boxster-wont-start-solved.html

[JFP in PA]

The Porsche Boxster alarm code I32 25: W Lead indicates a fault in the immobilizer circuit, often causing a no-start condition or immediate stalling. It typically signifies a failure in the communication link between the ignition switch and the alarm module, often linked to fuse E1, a faulty ignition switch, or a weak battery.

Ignition switch problems are common on these cars.....

[adrianw]

Hi,

Yes I am leaning towards the switch - hence why it sometimes works.

On the Euro cars, the alarm has a battery - so if you just disconnect the main battery the alarm will go off and off and off.

So you have to put the ingition 'on' to activate service mode - and then disconect.

I tried this while that car was giving me airbag errors and it would not go into service mode.

So I took that as a clue that fuse E1 was not doing it for the Airbag or i32 or i48 (it too tossed a 25 code but with different text).

Once I got the airbag and the E1 talking, I could put the alarm into service mode.

So I pulled the alarm/immobiliser stuff from under the seat and cleaned all the connectors on the black lead, just cause I could. They were all pretty clean anyway - a little oxidation perhaps.

I see that you can get the switch from about 10 [insert currency] where ever.

Or you can pay Porsche 240....

I will get a Meyle part or even the VAG part for pennies and give that a go.

Just hoping it is not anthing todo with elcectrolitic capicitors giving up the ghost.

I read a post by a proper engineer on how to solve that - scares me.

Cheers

Adrian

[Marc_986]

Give the switch a go first, it is cheap and good to replace anyway as it is known to cause issues.

While you are in there, you might consider taking out the lock mechanism / barrel, opening it up and replacing the old thick grease with fresh stuff. Also a common issue (with effect of not really turning the car off, thus draining the battery or being left with a key that keeps rotating, but no way to start the car).

[adrianw]

> you might consider taking out the lock mechanism

Yes I came across some discussion on this.

The people were debating the merits us using graphite over grease to prevent particulates accumulating in the grease.

I also found lock smiths decrying the use of graphite in locks too.

The lazy side of me wants to just squirt some ACF-50 into the barrel and not risk breaking anything during disassembly.

It is working fine at the moment, so I will probably leave it for now but thanks for hte heads up on a possible future failure.

My journey across the internet also gave me knowloedge about why I have lumps of black foam appearing in the airvents.

Another future job.

[adrianw]

Hi,

Yes it was the switch, airbag light and alarm systems happy again.

This is very hard to do on a right hand drive car - the grub screws face up into the dash.

I removed the side air vent and the internal hose that feeds it to be able to get one hand in the top to hold the ratchet in place while I curled the other arm up under the dash.

I've got long arms, part of the reason that I could not fit under the dash.

Cheers

Adrian

[adrianw]

Oh I got the part from a VW dealer for £15 including delivery (~$18)

4A0-905-849/B Ignition switch.