SRS Module/Airbag Light

[microtech1]

Hello,

I have a 2001 C2 996 that was imported to Canada from Japan recently. Prior to departing Japan, the car displayed no fault codes of any sort. During its transit to Canada I imagine the car was improperly jumped many times. I found the fuse box and battery cover misplaced when it arrived at my place.... so obviously the people moving the car didn't take care in properly jumping it. When I turned it on for the first time I found a airbag warning light on the dash. I have taken the following steps so far;

• I took the car to an indy who read out the codes as 3 and 195. The module was fried from the improper jumps.
• I proceeded to order a used module part# 99661821901 to replace my module of the same type. The used part was from a 2001 C2 and the production date was within 10 weeks of the original.
• I ordered a durametric to read the codes for the new module and to reset the light after I replaced the faulty module.
• I installed the used module and reset the codes.
• I was then left with codes for "driver and passenger belt buckles" I believe they were 46 and 49 or so. These codes are persistent and reappear after a reset nearly instantly.

I understand that the SRS module can be locked to a car, however the module appears to be working and is arming the airbags as there are no airbag related warning codes. Does this lock matter in this case if the donor car is nearly identical in equipment?
Should I take the belt buckle errors at face value and repair/replace them? These items appeared to have worked normally before its journey....
Is it possible the loom or contacts became damaged during the events that led to the SRS module needing to be replaced.

The car is in nearly mint condition with only 60k km on it. I do not think this is a dust/dirt issue. My temp permit has expired and I will not be able to get another one at this time. My only options are to fix the car myself or transport it to the dealer many many Kms aways. I would like to avoid the cost of a brand new SRS module, esp if the problem is not with that but somewhere else in the system. 

Any help you guys can provide would be great!

  

[Loren]

 

There is a Porsche TSB for this:

TSB 6924 1/04 Airbag Warning Light Comes On: Fault Codes 45, 46, 48 and 49

 

Your local dealer should be able to either do this for you or supply a copy for you to do.

It focuses on poor grounds and if that does not fix the problem then replacing the buckles.

 

[B3-CPO]

Unless I'm mistaken on the 996, the seat belt MIL is not related to the SRS module. I've personally had the dreaded "air bag light" thing too and other sensor issues. But, how do you know the car was improperly jumped? It's not uncommon for transport companies to pull the ignition fuse or disconnect the battery to minimize any electrical/mechanical damage during shipping and so seeing the panels removed shouldn't be surprising.  Are you saying that somehow the car was jumped off by the transport company and somehow fried the SRS module but didn't blow the fuse? And, if the car was fine, then are you saying somehow the battery died in transit? If it were me, I would have checked the car out with the driver as a witness and if it had problems, I'd file a claim. You did pay for insurance right?

 

Well anyway... moving on...

 

Re: the seat belt

There is a micro switch in the buckles that are known to go faulty. Replace the buckle assembly at the tune of $100 - $150 each and you should be fine. You may need to reset codes again once the new buckles are installed. 

 

 

[Loren]

There are twelve more pages to this fix...

[Richard Hamilton]

Bear in mind that the seat belt buckles on RoW cars are not connected to the airbag module, as they are with US cars.  I suspect that is your problem, as the car is a Japanese model and you have fitted a US module. The airbag unit is looking for a contact which doesn't exist.  The seat belt buckles on RoW cars are only connected to the instrument cluster, for the warning light and buzzer.

 

You may be able to work round this by re coding the airbag module to use RoW settings.  Alternatively, it would be easy enough to rewire the connector to match US spec.  I will look at the wiring diagrams when I get to my PC in the morning and post again. 

 

Edited June 27, 2018 by Richard Hamilton

[Richard Hamilton]

The diagram shows that the US buckles contain switches and resistors.  RoW cars only have a simple switch on the driver's buckle which is grounded when the buckle it inserted.  So to rewire it to simulate the US buckles is not as easy as I first thought.  If the wiring is in place under the seats, it might be possible to fit US buckles though.

This is what the WSM shows as the coding options:
The following equipment features can be changed:
– Driver’s/passenger’s airbag
– Buckle
– Child seat occupancy (passenger)
– USA (vehicles)

 

So I think your easiest option would be to get it re-coded, or just ignore the fault codes if you don't get the airbag light.

 

Edited June 28, 2018 by Richard Hamilton

[B3-CPO]

Good stuff, Richard!

[microtech1]

Wow, thank you so much Richard! This explains the reason why the two US sourced modules exhibited similar faults to me. Now, the dealer states that the SRS module is locked and cannot be modified in its 'locked' state. Is this in fact the case or is it possible to code the ROW features (or lack thereof) into the module after it has been put into service? Is the dealer trying to fish for a bit of $ out of me lol.

 

Unfortunately I cannot ignore the fault codes as it triggers the SRS warning light and therefore I cannot get it past a safety inspection in order to get it plated in my province. 

[Richard Hamilton]

Locking the module sets the vehicle type (986/996), but I am not sure if it sets the other parameters.  The section of the manual which describes changing the module says that after the new module is fitted it has to be locked, but nothing else.  The diagnostic manual says what I showed in my last post, so I presume it could be done after locking.  I have only locked an airbag module once, about 10 years ago, and can't remember what options the locking routine presented me with.  The only conclusive way to tell would be to plug in a Porsche Tester and try.  Running my PIWIS2 in simulation mode it looks possible though.

That option not being easily available to you, I would be tempted to see if the wiring exists to the X-16 and X-17 plugs under the seats.  If it is there, you could just fit US buckles, and you should be able to clear the faults.

Edited June 28, 2018 by Richard Hamilton

[microtech1]

Okay, I will weigh my options and see about doing one of the following;

• Having the dealer or an indy with a PIWIS2 attempt to code the feature
• Change the belts to the USA model
• Source a ROW SRS coded module of the same model/feature set

I will report back as I make progress. Thanks again!