Another Airbag Light Saga - Error Code 9886

[apple]

Hi there,

I just want to give a quick shout out to enuff_zed! He's been extremely helpful over the past couple of months but we've hit a bit of a dead end whilst trying to extinguish the dreaded airbag light! I have taken up much of his time, and two of his precious (SBSL) modules (which as we know, are like gold dust)!

My airbag saga seems slightly different from most so I thought I would see if the forum hivemind has any ideas on what I could try next...

The first replacement module resulted in the light being off for a day, a 100 mile journey, and 2 / 3 ignition cycles. However that evening the light came back on with a seat mat occupancy error. This error wasn't there before and the occupancy error was a communication error, rather than an open circuit error, when I checked in INPA. So we decided to meet up once again to try a different module as there was a good chance the module was also faulty (albeit not completely dead).
On our second meeting, the second module coded in successfully, and once again the light was extinguished. The seat mat error disappeared and all seemed to be working as normal when checked in INPA.

Before departing, I did multiple ignition on / off tests allowing the car to establish itself with the new module. 20 minutes down the road (after a petrol station stop), the dreaded light returned.
Now the current code is 9886 (Coding, firing circuit, knee airbag, front left (E85), or head airbag, left (E6x), at variance). Whilst this code has been mentioned a couple of times on other threads, nobody seems to have identified the specific fix for this error, and if there is something else that can be checked.
What does, at variance mean in this context? Also, this error mentions coding, could this mean something in the module has been coded / in or out on the previous vehicle which needs addressing?

Now there is an outside chance, this module also has a fault, which would make me extremely unlucky! If Martin was closer we could experiment with a third module. However, between us, we do think there is potentially another issue (wiring / plug corrosion??).

Is there anyone on here who could throw a few ideas my way. If i'm hunting for connector plug corrosion, is there anywhere in particular I could try? There are mentions of the firing circuit in the boot, although that seems to be more relevant to the 987B pre-tensioner error (which I did have but seems to have fixed itself now).

Sorry for the lengthy post, but I would like to sort the issue out. This issue could threaten a perfectly nice, well looked after Z4 if I can't MOT it.

Cheers

 

[enuff_zed]

Yup, this one is extremely frustrating. If we weren't opposite sides of the country it would be easy to keep throwing modules at it (if we could source them). It may well end up coming back to that but I am hoping we find a different solution.
I have fitted a few duff modules (a chance you take buying secondhand and the reason I won't travel that far until I have a couple of spares at least), but they have always immediately shown up as duds and the light won't go out.
In this case, it seems to take a few miles or more before anything happens. The only thing we disturb is the actual plug into the module. Maybe that has corrosion inside it?
I'm grasping at straws too!

 

[Mike6]

I probably don't know what I am talking about but what is the state of your battery.
If it's getting old or has previously been discharged might the circuits be protecting the starter mechanisms at the expense of other systems which then throw up faults.

 

[bigwinn]

My memory isn’t what it was, but I am 90% sure I had this code pop up on an irregular basis… which I solved by cleaning the passenger door connector block where all the wires pass from the door to the car: may be nothing but still worth a try

 

[apple]

I probably don't know what I am talking about but what is the state of your battery.
If it's getting old or has previously been discharged might the circuits be protecting the starter mechanisms at the expense of other systems which then throw up faults.

Hi, first thing I thought of.. but the battery is in good health and regularly have it plugged into my smart charger of the car is left for more than a few days without being driven.

 

[apple]

My memory isn’t what it was, but I am 90% sure I had this code pop up on an irregular basis… which I solved by cleaning the passenger door connector block where all the wires pass from the door to the car: may be nothing but still worth a try

Ok, great. Will have a scout around at the weekend.

 

[Usel]

Like Bigwinn says I would start by cleaning pins in connectors. Pull the connectors apart and then wash them with isopropyl alcohol using a small artist's brush and then connect and pull apart them a few times whilst they are still wet with isopropyl alcohol.

If you find any with noticeable blue/white crusting then concentrate more on those.

 

[apple]

I've just been looking back over my WhatsApp messages with enuff_zed, it would appear from my INPA screenshots, the last module shows the 9886 error existed alongside the seat mat error code (9895). As mentioned, we eradicated the 9895 code by swapping for another module... but I think the fact the 9886 code has been there for 2 replacement modules suggests something else is going on.

 

[apple]

Like Bigwinn says I would start by cleaning pins in connectors. Pull the connectors apart and then wash them with isopropyl alcohol using a small artist's brush and then connect and pull apart them a few times whilst they are still wet with isopropyl alcohol.

If you find any with noticeable blue/white crusting then concentrate more on those.

OK, I guess I need to put a fair weather day aside for this...
So the most likely culprits are the door connectors and the connector into the SBSL. Anywhere else?

 

[Usel]

There's a little black box under the passenger seat for the occupancy sensor. I'd say it's worth trying a different one.

Tbh I could send you out a passenger seat belt pretentioner and little black box if you cover postage both ways so you can test. You can connect these up without removing the seat and bolting them on if you're flexible enough.

 

[Usel]

I don't know how the sbsl would react to isopropanyl alcohol on the optical part within the connector so don't put any on that bit. It looks obviously different to normal male and female pins so easily avoidable.

 

[apple]

There's a little black box under the passenger seat for the occupancy sensor. I'd say it's worth trying a different one.

Tbh I could send you out a passenger seat belt pretentioner and little black box if you cover postage both ways so you can test. You can connect these up without removing the seat and bolting them on if you're flexible enough.

Even if my only code doesn't refer to those issues?

I can see both the occupancy sensor working correctly in INPA, and the passenger belt seems to be doing its thing also. Although, I accept there are more complicated relationships going on between these sensors and the various bits of electronic witchcraft.

 

[apple]

I don't know how the sbsl would react to isopropanyl alcohol on the optical part within the connector so don't put any on that bit. It looks obviously different to normal male and female pins so easily avoidable.

 

[Usel]

There's a little black box under the passenger seat for the occupancy sensor. I'd say it's worth trying a different one.

Tbh I could send you out a passenger seat belt pretentioner and little black box if you cover postage both ways so you can test. You can connect these up without removing the seat and bolting them on if you're flexible enough.

Even if my only code doesn't refer to those issues?

I can see both the occupancy sensor working correctly in INPA, and the passenger belt seems to be doing its thing also. Although, I accept there are more complicated relationships going on between these sensors and the various bits of electronic witchcraft.

I play about with seats. I put facelift seats to test the heated seat part works in my prefacelift. Sometimes an airbag light is thrown up immediately and other times I get no errors at all and everything works perfectly. It shouldn't work at all because it's completely different technology.

The occupancy sensor is a fickle beast and the pretensioner isn't much better at times.

 

[apple]

Ok, so i finally got round to checking the connections on the door connector and I also had a look at the passenger SBSL module connector to see if there was any obvious corrosion, and nothing obvious unfortunately.
I've given everything a liberal coating of contact cleaner, and error 9886 continues to stubbornly reappear on every ignition cycle after clearing the code.
Seat connections were also checked a few months back...

I'm thinking the next check is taking off the door card, and checking the plugs for the airbag in the passenger door?

 

[enuff_zed]

Ok, so i finally got round to checking the connections on the door connector and I also had a look at the passenger SBSL module connector to see if there was any obvious corrosion, and nothing obvious unfortunately.
I've given everything a liberal coating of contact cleaner, and error 9886 continues to stubbornly reappear on every ignition cycle after clearing the code.
Seat connections were also checked a few months back...

I'm thinking the next check is taking off the door card, and checking the plugs for the airbag in the passenger door?

Yup you have to cover every possibility.

 

[Mike6]

I had a car where windows just wouldn't function properly all the time. In the end I tracked it down to a deteriorated cable in that bunch of wires that exits from the car body into the door itself. Continuous opening and closing of the car over a long period of time must have weakened the wires which then only made intermittent contact
Worth a look?

 

[enuff_zed]

I had a car where windows just wouldn't function properly all the time. In the end I tracked it down to a deteriorated cable in that bunch of wires that exits from the car body into the door itself. Continuous opening and closing of the car over a long period of time must have weakened the wires which then only made intermittent contact
Worth a look?

Definitely!