So the days I drive the cat, weekends, every time I start it in the morning I get the airbag light. If I drive for 20 minutes, stop, turn off the car and start it again I don't see it for the rest of the day. This happens Saturday and Sunday of course. This even happens even though I put a trickle charger on it. I have also been driving and it just goes off by itself. So is this a power issue? Would that cause a airbag light

 

ONLY THE MODULE KNOWS FOR SURE!!!!!!!!!!!!!!!!!!!

DTC in the module will reveal what fault is causing the MIL.(let the guessing begin)

 

Steering column control module ?

 

So is that the the module and if so can I just replace it?

 

You tinkered with it on steering column replacement , and this would be the data bus wire that passes through the ABS / TC module , instrumment cluster , steering column control module , and others

On the left rear speed sensor circuit . the inductance signal ( not data bus ) passes through the ABS / SC module on its way to the variable steering speed amplifier and the instrument cluster

You had a issue with one of the rear instrument cluster connectors

But the easy try would be to remove the fuses a depower the devices ( 3 for the IC ) if they were to be corrupting the 2 different signals

Your fault light showing up on starting it may be a before it gives the system to you bite test ( there is a better word for it ) and not a functional fault

 

Hmmm so which fuses are you speaking of? The steering control Module. Also what I think is very interesting is that I can start and drive my car 10 times during the day and the only time it comes on is that first start before I drive it 20 minutes. Also if I drive it with it on eventually it will turn off. The battery is new and I keep it on a trickle charger over the week. I tried to run a diagnostic but nothing comes up

 

Not all code readers are going to see the airbag module , lucky to find one that sees all transmission codes , T codes

Have you reviewed the X300 Airbags for Dummies doc ?

He recommended in a post to not altering the 2.5 ohm test resistors

Fuse list coming

 

If you have a link. I will check the sticky section

 

I have the file and will upload

The doc was made by Brendan Mc Phillips , bimcp

 

I found it and print it out. I will go through it but there is a good chance that I can go through one test and the next time I go to test it again that it may not be there. Based on the faults at the bottom the only thing that I can think of it could be is the first fault, or low battery, or a Back‐up Power Supply ‐ Voltage Boost Fault (Whatever that is). What I am thinking is that driving the vehicle charges the battery and that is why the fault goes away and overnight the battery drains a little and that is why I get the fault. I noticed when driving that the battery is charging about 14-14.5V

 

I think there is a self-contained battery inside the airbag module

 

Hmmm. I have an extra module. Maybe I just swap it out and see if that fixes the problem. I am sure that when someone has a battery issue on their car their airbag light does not go on and I am pretty sure that my battery is fine. Like I said I run a trickle charge on it. Maybe that battery does not charge until the vehicle is started and runs.

 

Here is a link to the board and does not appear to be a battery. Appears that there are a few capacitors in there that might store the energy. I think that is what they are speaking of "Reserve Power" in the diagram in the PDF

https://www.jaguarforums.com/forum/x...module-134360/

 

Start up bite test or a different change over power source from the self contained battery to the main battery bus

This would be opposite of a as you crash senereo of coming from the battery bus and a interrupted battery bus reverting to the internal battery

The inertia / crash switch plays a independent role from my understanding and is only looking at the different crash sensors at the front car grill and one on the side by the front right door hinge

airbag control module have a good ground ? This may be in the form of a pin ground or a dedicated case ground wire strap like the ECU

I don't recall there being a dedicated case ground as my airbag control module is still out of the car and have not activated my replacement air bags from the previous owner's accident

 

Here is a link to the board and does not appear to be a battery. Appears that there are a few capacitors in there that might store the energy. I think that is what they are speaking of "Reserve Power" in the diagram in the PDF

Yes I see the heat damage of the adjacent white device but would expect a larger Cap to be able to fire off the squibs

We switched from internal batteries to Caps in other similar devises in the airlines based on delay driven reliabilities , Floor egress path light trigger monitors

 

When I have some time I will go ahead and swap it out and then take a look at the one I swaped out to see if there is any internal damage. I am just wondering if the cap has drifted and not holding a charge anymore. I know if unused for a while they could eventually go bad but of course, this has been used a lot. I am thinking that when I run the car for a while it has time to bring it back into tolerance...for a little while and then as it sits it drifts enough that that is where I am getting the fault. I am not sure if power is applied to that module continuously or if is just when the car is started.

 

There are 2 fuses to the airbag module , a main power and a separate one that in part feeds the power storage device inside

Wil look up if the fuses are hot at all times or rely on the fuse box king relay to close in the starting sequence

Need to run to the store

Just got my cancer report back after deep testing and results were never had cancer and that puts me in the kidney transplant list at KU

Look for a can Cap like in the pic on the other thread you linked , this will probably be wired directly to the output pins of the control unit to fire the squibs in the airbag

 

OK, I will take a look. I knew a few years back you were having medical issues and thought you were all good because I heard nothing. Well man, take care of yourself. Good luck with finding a donor. You know until you hear things like this we all take life for granted. I will keep you in my prayers. You have helped so many people here and you continue to be a resource that I am sure everyone has used, We all owe your our gratitude......especially me.

 

Fuse # 17 right heelboard fuse box hot at all times , airbag power starage device inside module

Fuse check on this one , you never know

Fuse # 16 trunk requires the trunk fuse box relay ( King Relay ) to close , this is your main power to the airbag control module located way back in the trunk but it was a add on design so where ever empty fuse space was located

 

All the fuses are good. Time to take a look at the module or at least replace it. So here is what the module looks like