Persistent little air bag light.

[Tonka]

I unwittingly left key in ignition (E85) and when I released where the key was the next day and tried to start engine it became apparent that keys in ignition overnight equals flat battery, even when ignition was turned off. Discovered this after turning the house upside down and blaming the missus for moving it (did feel an ass when I had to fess up as to where they were).
Can anyone help with an always on air bag light I've acquired since lost key escapade. Had no gauges or indicators initially as well but sorted that by removing and replacing fuse on advice of a mechanic mate of mine. He's had the car plugged in but shows no faults.

Any thoughts/advice would be very much appreciated.

 

[Smartbear]

If your battery is below par it can bring on all sorts of weird issues, I would look there first.
Rob

 

[Scooba_Steve]

Has the battery been fully recharged?

 

[Tonka]

Yea good point, but battery never a problem before and once charged through optimizer never skips a beat. Just the infernal air bag light problem. MoT 19th of this month so need to remedy before then.
Thanks for the post though Rob.

 

[Tonka]

Yea good point, but battery never a problem before and once charged through optimizer never skips a beat. Just the infernal air bag light problem. MoT 19th of this month so need to remedy before then.
Thanks for the post though Rob.

 

[Tonka]

Batteries good, fair whizzes over when engine started. Not let me down before or since.

 

[cj10jeeper]

I don't see how the 2 events are connected. Weak and low batteries cause all sorts of issues that are cleared once the new battery is fitted and perhaps a few user resets such as window closing at fixed. Never heard of an airbag issue.
You need to get it plugged onto a diagnostic tool, identify the cause and reset the fault

Cable off eBay for £30 with software will fix it

 

[kis]

Agree with CJ. Battery may be all good now but you'll need to reset the fault code before it'll disappear. Some sort of code reader and fault reset device is needed... unless you've already reset it!!

 

[Mr Tidy]

Sounds like 2 unconnected incidents OP; they just happened at the same time!

I had an air-bag warning light illuminate on my E46 a year or so ago and took it to my local BMW indy for diagnosis - it seems there was a one-off problem with the driver's seat belt pre-tensioner, but anything triggering an air-bag light doesn't reset next time you use the car; it needs re-setting through the On Board Diagnostics.

I'd recommend a BMW indy or buy a specific BMW reader yourself. Unless your mate specialises in BMWs, his code reader is probably a generic one so is unlikely to won't provide as detailed a diagnosis as a genuine BMW or BMW specific one.

Hope you can get it sorted.

 

[kis]

air-bag light doesn't reset next time you use the car; it needs re-setting through the On Board Diagnostics.

This.
May possibly be two unrelated incidents, or maybe they are related somehow?

Best way to check is to diagnose and systematically rule out each fault. Then reset, if they re-appear you know you've got an issue... but hopefully they all disappear! Just make sure you take a good look through each fault code before you hit the reset!

 

[Tonka]

Just back from first proper run this year and the air bag lights still on. My goodbuddy mechanic mate suggested it might be a good idea to let the CPU do a full check re engine temps, types of driving etc, alas to no avail.
He takes delivery of a better, more up to date diagnostic piece of kit next week, so as pointed out it's got to be the way forward.
I'll post when we have a solution.

Thanks to all for your direction.