SRS error after changing clock spring
 

Hey all,

I recently changed the clock spring on my '07 HR 350z, due to the horn no longer working. Since doing so, the airbag light has started flashing. The flash pattern I'm getting is 1 long followed by 1 short. A scan with NDS II revealed the following error code: b1081, pre-ten front rh.

No accidents or malfunctions were witnessed, and airbags have not deployed during the car's lifetime. Unsure if this is a common issue, or if I'll need to replace the SRS module? Anyone have experience or knowledge on the issue?

Thanks in advance!

Bumping this one... If anyone has any ideas, pls let me know!

That's very odd, B1081 is for the Right Front Seat Belt Pre-tensioner.
The circuit is "open".

The clock spring replacement could be completely unrelated to this issue.

When you replaced the clock spring, did you have the battery disconnected and wait 5-10 min before proceeding?

Has any other work been done recently on the vehicle that may have involved interior wiring?
Cheers!
-Icer

I know right! The battery was disconnected - didn't wait 5-10 mins, however did pump the break, turn the key a few times, etc to try and drain the system as best as possible. Otherwise no other wiring work has been done (to my knowledge, at least).

Pumping the brake and turning the key may not help in this case, I believe the SRS system has it's own capacitor that is unrelated to the ignition system. But I think you're probably safe in this case since you don't have any stored codes for the steering wheel airbag (must be removed to replace clock spring).

This will require some review of the wiring diagram for the SRS system and this pre-tensioner. It's very possible nothing is actually wrong with the pre-tensioner itself, it could just be a poor connection somewhere. But to rule out the clock spring, we need to check the wiring diagram. Just to confirm, the seatbelt is working correctly? Meaning it's not locked out or failing to retract?
Cheers!
-Icer

@icer5160 Oh the more you know! I didn't realise the SRS was on a somewhat independent system. Seatbelt does seem fine, though it is a touch weak to retract (sometimes needs a bit of guidance to help it re-spool) when unclipped. I figured this was just from the car being older. It would have to be insanely coincidental timing for that circuit to fail at the same time I replace the clock spring though, right?

Ok, here's the wiring schematic for the SRS system. Now this is for a 2006 350Z, but I don't believe the SRS system really changed between the years. Some additional airbags might be present, but the overall wiring is more or less the same.
https://cimg1.ibsrv.net/gimg/my350z....6b2907b21f.png


The Seat belt Pre-tensioners wire directly into the SRS control module, located under the center console, directly under the arm rest and cup holder area (hope you didn't have any nasty drink spills recently).

The clock spring, which is noted as "Spiral Cable" does interact with the SRS system, but only for the Driver/Wheel Airbag.

At this point, I do find it hard to believe that the issue is actually with the Seat Belt pre-tensioner. More likely, the clock spring replacement is related. Where did you source the part? Is it new, OEM?

The blink code you got is correct (one dash followed by a dot, and repeats) for the RH belt pre-tensioner. I would try re-scanning the SRS system with a different scan tool, NDS-II should work, but just to be sure the code referenced is accurate. Worst case scenario, there could be a short with the replacement clock spring and that may be causing the SRS control module to act up...or your SRS module is toast. Do you still have the old clock spring? A quick test would be to reinstall the old one and see if the SRS codes disappear.

If swapping the old clock spring in yields no results, and you're confident that the scanned code and blink code are correct, then the next step would be to run continuity tests for the wires to pins 7 and 8 at your SRS module back to the LH pretensioner. Basically verify you have continuity between pins 7 & 8 at the module, if you do, then the tensioner should be good and your module could be bad. If you don't have continuity, then check continuity from module to the tensioner, if those check out, then the tensioner itself is bad. This will take more work since you would need to remove the center console and interior paneling around the seatbelt to expose the wires (and of course disconnect the battery and wait at least 5 min before touching wires). Quick tip, whenever disconnecting your battery, roll your windows down beforehand, so you don't chip/damage your sill panels when opening/closing the doors. The window glass won't crack open without power!

If you get to that point, obviously check for corrosion or damaged wires. Worst case scenario, you need to replace the seatbelt or have it sent out to have the tensioner rebuilt. This is a pretty common service for repairing collision damaged vehicles.
Good Luck!
-Icer