Instrument Cluster Icons Behaviour

[Rabbers]

When, ignition ON, the icons in the instrument cluster light up, they all do so simultaneously.  But then, once the system check is complete, they disappear in a process that is too quick for the eye to fully register but is clearly sequential and not simultaneous.  My only certainty is that the last icon to disappear is the Airbags (SRS) one.  Although I am now on my second RC300h F-Sport, I frankly can’t remember if the sequence was the same when the cars were new, but my suspicion is that it might have changed in both cars.  Is it possible that  the system check reflects, or is perhaps programmed to simulate, the extent of age-related wear and tear on the individual functions so that the last icons to go out represent the likeliest (though hopefully still improbable) malfunctions within the system?  

[Herbie]

23 minutes ago, Rabbers said:

Is it possible that  the system check reflects, or is perhaps programmed to simulate, the extent of age-related wear and tear on the individual functions so that the last icons to go out represent the likeliest (though hopefully still improbable) malfunctions within the system?

Purely a guess, but I'd say that there's not a cat in hell's chance of that happening.

[Rabbers]

4 minutes ago, Herbie said:

Purely a guess, but I'd say that there's not a cat in hell's chance of that happening.

Do you mean it’s technically not feasible or that its prospective usefulness by way of forewarning would be dubious?

[dutchie01]

Somehow i think this catastrophic problem does not appear on other car forums and could tell something about Lexus reliability.

Or, as the Germans have a saying, Can i have your problems please?

Renato as a true philosopher will this keep you awake at night? Could there potentially by an issue with the airbag and why if at all has the sequence of the lights going out changed, what is the underlying message from Lexus Japan and what will go first the airbag or the warning light?

[Herbie]

2 hours ago, Rabbers said:

Do you mean it’s technically not feasible or that its prospective usefulness by way of forewarning would be dubious?

Just that I've never heard of any car where this happens and also that there's no mention of it in the owners manual.

I don't know why or even if the sequence of warning lights would change, but I think you're reading too much into it if you think it may be an advance warning system for age-related defects.

[Linas.P]

I think you reading too much into it. Simply said lights means that that systems are ready for self-check, when you start the engine they complete simple response via can-bus reporting that they are working and the lights goes off. I don't think there is any meaning in the sequence, it may be programmed in the Getaway ECU to send sequential command to each module, or it may be based on the module location on the can-bus. In either case airbag going off last is unlikely indication of any fault, perhaps there are more checks linked to airbag light and it takes longer to confirm all parameters are right. My only guess is that your second car is later model with LSS+, which means that you distance radar and other things have to self-test before airbag light goes off, whereas older model didn't need to check distance ECU... so airbag light just takes twice as long to go off, because it needs extra module to respond.

[Rabbers]

10 hours ago, dutchie01 said:

… as a true philosopher will this keep you awake at night? ….

Believe me, Bernard, it takes a lot more than this to keep me awake at night, especially as true philosophising is something I am perfectly happy to leave to others.

I will add, though, that it would be legitimate, after falling asleep, to dream of a systems check that gives advance warning of a possible malfunction so that you could contact an “authorised Lexus repairer or other reliable repairer” in your own good time and not as a matter of urgency or with a stopped car.

[Linas.P]

Well that would be unreasonable expectation - you basically want car to have a crystal ball and predict the future 😄 

Sadly not how systems work, not the type of the failure mode they can have as they are based on electrical signals and basically have a range in which they pass the test (e.g. 2.4-2.6V) and values which are outside of allowed range and then they report fault. On top of that in modern cars almost everything is unit replacement, so although I agree it would be more convenient to spend £3000 at the time convenient to you rather than when broken down on the side of the road... it still means spending that £3000. Thinking about it further  - I don't believe any manufacturer would willingly include such feature as it would mean people could claim warranty on parts which are about to fail, instead of those parts failing outside of warranty, so this basically would be extra step to take which would directly hurt their margins. Just cannot see it happening.