The Lotus Cars Community banner
  • Hi there! Why not register as a user to enjoy all of the benefits of the site? You may register here. When you register, please pick a username that is non-commercial. If you use a name that appears on any search engine commercially, you must pick another name, whether it applies to you or not. Commercial usernames are for supporting vendor use only. If you want to become a supporting vendor and grow your business, please follow this link. Thanks!
41 - 60 of 91 Posts
From what I have been told from a person who knows, in an event when an SRS system has been told to deploy, it will try and deploy even if it thinks theres an issue with the system downstream. It will default to deploy. Ie if you un plug an airbag it will still try and deploy that bag. An upstream fault is different and needs to compare scenarios so that it wont deploy when its not meant to.

There are dozens of conditions that need to be met and possible scenarios that could cause them. When the light is on, particular scenarios may no longer work but others will.
Maybe for example if you have a faulty seatbelt tensioner it now disables the steering wheel airbag, because youre going to hit the steering wheel anyway, so no point in then exploding a bag in your face. Who knows?

We have no idea how its been programmed. We have no way of knowing if ours will deploy because we dont know the reason for the light being on. But we can say that its more likely to deploy then not if its just some voltage spike/drop or a sensor being slightly out of bounds.

So in summary, yeah it may or may not deploy.😄
 
This connector relates to the side air bag built into the seat. What year did Lotus add the side air bags? My '11 doesn't have them. Did it start with the 400?
 
Discussion starter · #44 · (Edited)
Following the advice from the Lotus documentation posted earlier in this thread, I lifted the passenger seat and cycled the SRS connector two times. It made zero difference. Then I ran out of daylight so the driver's seat will have to wait for another day.

For the benefit of others who may want to do this, here are some notes. First, a photo of the seat heater connection:

1268912


Note that the two adhesive tyraps holding the two heater harnesses are hanging in free space. That was a common theme under the seat. The adhesive mounts are worthless, they do not adhere to the seat at all.

Next, a photo of the SRS wiring harness and the connector in question:

1268913


Look toward the bottom of the photo (which is the rear of the seat) and you can see another of those adhesive ziptie mounts, hanging in free space. Zero adhesion. However, the SRS harness and connector are held in place by three zipties which are themselves held to the seat by three of those push-in mounts like so many other automotive trim pieces use.

Now that you know what you'll see, here are my comments and observations.

1) Removing the seat floor bolts, especially the rear ones, is difficult and time consuming. They are hex head bolts and there is no vertical clearance for a traditional hex socket on a ratchet handle. I have a lot of tools and nothing I own would fit well in the available space. I resorted to a 6mm right angle Allen wrench to loosen them, then a 5.5mm ball-end Allen wrench to rotate them out.

2) Cut the three tyraps immediately. I tried to separate the connector without cutting the zipties. It's impossible, at least for me. I tried removing one, then two, and finally all three and it was still a contortionist's nightmare. And this was on the PASSENGER side where there is potentially more room.

3) The connector instructions say to pry the handle of a "suitable" screwdriver away from the connector body and harness. The instructions are wrong. Instead, take a 1/4 inch flatblade screwdriver and insert it as shown in the illustration. Then pry the handle TOWARD the connector body and harness. This is much more effective at releasing the latch and allowing the connector to separate.

4) Even with the above tricks... even after doing it once already, and then reconnecting the connector... separating the connector is a PITA. You need at least three hands but there's really only room for 1.5. The hand that has to hold the connector and manipulate the screwdriver would benefit from at least one extra finger and all fingers should be double-jointed.

5) You will be hanging upside down in the passenger footwell the entire time. I have no motion/orientation problems whatsoever and even I experienced a bit of vertigo when I finally got them separated and had the chance to stand vertically again.

6) For such an elaborate connector, there are exactly two contacts inside. The airbag connector contacts are gold plated. The vehicle's harness connector contacts are not. They might be nickel but look more like zinc. Such connectors can be the source of some excess resistance but I didn't see any corrosion or contamination. Nevertheless, I disconnected, reconnected, disconnected, and reconnected again (total of two "wipe" cycles) since I was under there anyway.

7) This connector actually comprises two connectors (one from each harness) and a central housing that has another of those trim-like retainer clips that snaps into the seat bottom. That red latch they warn you about retains the seat's connector to the central housing, which is why you don't need to remove it.

8) Pay careful attention to the Lotus illustrations. There are a lot of places on the central housing that LOOK like they should be latch releases, but they're not. You have to use the correct access point, and you must have the screwdriver in the proper slot (there are two, side by side).

9) Be sure to replace the tyraps with three similarly-sized units. The ones I used are 4.5mm wide and they appeared to be a perfect match.

10) When reinstalling the seat floor bolts there is no way I could figure to get a torque wrench in there to set them to 30NM - and I have several different kinds and sizes of torque wrench. The problem, again, is vertical access above the bolt head. I am a good judge of torque on a wrench so I used some blue (removable) threadlocker and torqued all four to approximately 30NM.

11) They aren't kidding when they say you'll have to reset the windows when battery power is lost. However, the procedure works exactly as described except that I had to hold the buttons down, then up, for much longer than I expected.

12) The latest Alpine head unit which ships in the Evora GT does NOT lose its programming when power is lost. Thankfully, it appears to retain everything in nonvolatile memory. It remembered and connected to my cellphone, it remembered the radio presets, everything. That's better than every other car I've ever owned.

After a good two hours of this, I started the engine and nothing had changed. The SRS light blinked a few times and then stayed on solid. So either the problem is under the driver's seat, or there is a genuine problem with some component in the airbag system. I really hoped it was under the passenger seat but other than gaining experience with the car, I accomplished little. Sigh.

Hope this helps someone!
 
  • Like
Reactions: Brookliner7
Taking the seats out is not difficult. Disconnecting the airbag connectors is fiddly, particularly since you have to do it with the seats in the car. You need a small flat screwdriver or a pick to release the clip and its not obvious how to do it. Also the harness is zip tied to the underside of the seat so you need to cut or release these before you can lift the seat up to access the connector. The other key issue that I am sure you are aware of is to leave the car off for 30 mins and disconnect the battery before you start and of course don't turn it back on until the airbags are reconnected. I sprayed mine with wd 40 contact cleaner before putting it all back. I have not had this problem myself but could imagine that if you use the car in wet weather water/condensation under the seat could be an issue.
 
That is a useful write up- I wish I had those pictures when I took my seats out. Thanks for posting.
There are threads here about resetting the airbag light/code using OBDII diagnostics but I have not seen this for the 4xx cars. The Lotus scan tool/software is called TechCentre and its expensive and unfortunately too niche for anyone to make a knockoff version. I wonder if there is a way for the dealer to do this for you remotely?
 
Because so many of us have dealt with airbag lights, I reached out to Dave Simkin, National Technical Manager, Lotus Cars USA. Below are his two replies, verbatim, reacting to the original post in this thread. Helpful information. Bold accenting is mine:

First reply:

It is most likely the seat airbag resistance reading high. GM suffers with the same concern to the point they eliminate the connector and hardwire the seat bag. We do not condone this and cleaning / Resecuring the connector will take care of it. We do put additional fixings to eliminate the possibility of the connector moving when the seat is moved back and forth on the runners. The connector itself has a specific way it is released and I can email that to you tomorrow. Once the resistance is corrected the light should go out. While the light is illuminated the SRS system is inoperative
David Simkin
NATIONAL TECHNICAL MANAGER – LOTUS CARS USA


Dale:
Attached is info on releasing the SRS seat connector. The connector also has what appears to be a red locking clip, DO NOT TRY TO REMOVE THIS as irreparable damage will occur resulting in the need for either a seat or main harness replacement.

pdf attachment below:
Thanks for valuable info. In past, trying to remove driver seat I ran into the problem of disconnecting airbag, and thankfully stopped before damaging the harness. Now I can see why was unable to separate. Again thanks for good info.....
 
Discussion starter · #49 ·
I've pulled the driver's seat and cycled its SRS connector. In today's better light I can see that the airbag's connector does in fact have gold contacts. However, the vehicle's harness connector has the silvery nickel? zinc? contacts mentioned earlier. I've corrected my comments above to reflect this.

The driver's seat rear floor bolts have somewhat easier access than the passenger seat's. However, the driver's front floor bolts are even more difficult. Odd that they're different.

One of the three adhesive tyrap mounts (the one on the SRS cable) was still adhering to the bottom of the seat. The two on the seat heater harness were hanging free, just like on the passenger seat.

The frontmost tyrap on the SRS harness was absolutely CRUSHED onto the wires. Fortunately it has loom around it so the (rather small) wires inside are probably OK but seriously, that thing was really on there. I won't be crushing its replacement quite so much.

I must say at this point that the length of the SRS harness coming out of the floor seems a bit too short. I know, "lightness", but I'm seriously wondering if there's enough length to prevent the harness from being yanked and jerked whenever the seat is adjusted all the way forward or backward. I don't see any physical damage but even one more inch of length would inspire a bit more confidence and only weigh a few grams. (The twin heater harnesses are significantly longer, so why must the SRS harness be so short?)

Going back to reinstall the seat and then see if cycling the driver's SRS connector made any difference. Honestly, based on what I've seen I don't expect that it will. I believe it will turn out to be a failed component in the SRS system somewhere that the dealer will have to replace next spring.
 
Has anybody actually had a diagnosis of some component failing when having a dealer address the airbag light? I’ve never heard of that happening. In my case, it has always been “we cleared the light for you”, end of story.
 
Discussion starter · #51 ·
Reinstalled the seat. Then, since the battery was disconnected anyway, I measured its unloaded voltage with my calibrated Fluke meter: 12.74VDC.

Then I removed the battery and confirmed its little "eye" is green, indicating good health. Then I took it to our local NAPA which has our nearest battery load tester. It's not a true carbon pile, but it's nicely instrumented and gives you various details about the battery including its real-life CCA measurement. That meter read 12.83VDC and reported 100% capacity and 700 CCA.

Every test, with my own equipment as well as that of others, indicates the battery is in perfect health. Therefore I seriously doubt the battery caused a low voltage event, and in any case the docs say a low voltage event does not generate a code and is self clearing (the tell tale light will go out on its own).

I reinstalled the battery, connected the cables, powered up the car, and started the engine. Everything worked perfectly - but the airbag light remains on solidly.

So:

  • We know it's not the battery
  • We know it's not the connectors and wiring under the driver's seat
  • We know it's not the connectors adn wiring under the passenger seat

...therefore I conclude 1) there was either a transient event that threw a code that gets "locked" into memory until it is later cleared, or 2) there really is a faulty component somewhere in the airbag system.

There are quite a few threads on here where people have reported certain specific OBD2 readers, with non-US car data, have been able to clear airbag codes on Evoras. That's the last option I have before waiting for the dealer next spring. Anyone know if there is a presently available OBD2 reader that has been successful on the airbag light in a recent Evora?
 
Discussion starter · #52 ·
Has anybody actually had a diagnosis of some component failing when having a dealer address the airbag light? I’ve never heard of that happening. In my case, it has always been “we cleared the light for you”, end of story.
One of my two working theories now is that the electrical system can suffer a transient event which fools the SRS into believing there was a locking (e.g. "throws a code") event that must be reported. The only way I can (dis)prove that is to find an OBD reader with a proven history of clearing airbag codes, as I mentioned above. There are threads here where folks claim they've done that successfully. I'm hoping some of them chime in here so we can run that test.

I feel like we're gathering a bunch of data about the Evora GT. I just hope we're able to finally answer the questions and document them here for everyone's benefit.
 
I don't think anyone has had success clearing the airbag light on the S2s with any of the readers. Seems Lotus caught wind of @bakhteria's findings and changed things around.
 
Discussion starter · #54 ·
I don't think anyone has had success clearing the airbag light on the S2s with any of the readers. Seems Lotus caught wind of @bakhteria's findings and changed things around.
Drat. I thought some of those threads were speaking of recent Evoras.

The understanding I'm starting to glean from these discussions of SRS's suggests that the OBD readers interact directly with the SRS controller and not "through" some Lotus-built master device. Thus it should still be possible to clear SRS faults - we just need to figure out what SRS controller they switched to and find a reader than knows about that unit.

SRS's are pretty specialized, I wouldn't have thought there'd be a large number of separate manufacturers out there. Sort of like the airbags themselves, there's only a handful of companies that make them.
 
Discussion starter · #55 ·
In my haste to wrap up documenting my under-seat connector adventures I forgot to mention that I did find a broken tyrap on the seat SRS connector. I replaced it with an identical one. Here's a photo just before I trimmed off the excess material:

1269082


This connector does NOT come out of the central housing... you can see the red retention clip in the photo above. The connector that does come out is on the other end, and is tied to the vehicle wiring harness.

The tyrap's strap had been snapped but the tyrap was still in place on the connector. The red and black wires have little grooves in their insulation where the tyrap pressed against them. No idea if the wires were tugged hard enough to snap the tyrap (that would take some serious force) or if the tyrap snapped during installation. I almost missed it, so it's easy to understand how it could have been missed in Hethel during vehicle assembly.

I mechanically checked that the wires were still engaged in their contacts. I did NOT electrically probe the wires to confirm continuity, as I don't know what signal is used to trigger the airbag and I wasn't interested in accidentally doing that. It's likely well more than my Fluke meter uses in its low resistance ranges but just not worth the risk.

Now that I look at it, that photo is useful in another way. Precisely where to use the screwdriver (mentioned above) is not necessarily clear from the Lotus illustrations, so here's an annotated photo:

1269083


The locking tab area is a bit out of focus because I took the shot to illustrate the tyrap, but everything is still visible. The point is that the screwdriver goes into the slot nearer the central housing body ("under" the locking tab), not in the slot between the locking tab and its protective cover. As a reminder, once the locking tab is lifted out of engagement it is the vehicle harness connector on the OTHER end of this assembly (not visible in this photo) that slides out of the central housing. The SRS connector (shown above with the red and black wires) remains in the central housing.
 
Hey! This was a huge help- Thank you for taking the time to clearly explain this PITA plug- Even with your detailed instruction it sucked, but I wouldn't have know where the lock is without this pic-
 
Discussion starter · #57 ·
You're very welcome. We're all in this together!
 
I have been living with an inexplicable airbag light for over a year now. This is after Lotus cleared it with tech center or whatever they use which didn't do anything. Sigh.
 
Discussion starter · #59 ·
When mine goes 350 miles back to the dealer this spring it's getting a new wiring harness. That's what the technician diagnosed last time as the cause for my airbag light. He cleared it but it came right back, and after measuring the wiring he found either a short or an open which means new harness. Lotus USA already approved the work but they didn't get the part in time before I had to drive home.
 
When mine goes 350 miles back to the dealer this spring it's getting a new wiring harness. That's what the technician diagnosed last time as the cause for my airbag light. He cleared it but it came right back, and after measuring the wiring he found either a short or an open which means new harness. Lotus USA already approved the work but they didn't get the part in time before I had to drive home.
Interesting. Wiring harness for what? For the airbag connector? If you can share part number and possibly photos of the unit they replace, it would be highly appreciated.
 
41 - 60 of 91 Posts