Here's one that will look good in the hole.

 

Well, this is a unique turn of events!

I found one thread about a person that had their clock running fast for a bit and when they had the dealer service it, they were told the battery was replaced under warranty for failing. Magically, their clock started working again.

Armed with this knowledge, I checked my overnight battery voltage at just over 12.2V. That evening I set the clock to the correct time and put my 2AMP battery charger on it overnight. The next day the battery was showing 13.1V and the clock was 15minutes fast. I figured it wasn't working and I'd pretty much just run it back 15 minutes every time I got in it.

I didn't drive it over the weekend as we had company and drove in my wife's car.

This morning, I got in the car and checked my phone, ready to run it back 15 minutes or more after the weekend but low and behold, it was 5 minutes SLOW!

So, I'm going to leave it 5 minutes slow and see where it is at lunch and this evening.

That's another tool in the arsenal if anyone has a fast clock in the future if this pans out.

 

Mysterious as well as perplexing. It sure sounds like the battery's voltage may be exceptionally critical to the clock keeping accurate time. Keep us informed...

 

It was exactly 5 minutes slow this morning, April 30th, after having not been touched since Friday, April 26th. I have set it to the correct time and we'll see where it goes.

It could be a voltage issue but I can't imagine 12.1V being so low that the clock would run fast. If it is truly that delicate, I can see the shop leaving the door open while they fiddled with the tires, TPMS or even left the radio on and drained the battery a bit more than normal. In that instance, literally, putting new tires on it did cause the clock to run slow.

Purely speculation but that's the simplest answer that checks all the boxes I have observed.

 

It sounds like you have enabled the "Time Machine Mode" in your settings menu. Be very careful. There are some tire size settings that can thrust you backward to 1945. This is all covered somewhere in your manual.

 

But then wouldn't every GS out there with a less than stellar performing battery have this clock issue?

 

How old is your battery, is it stock? Have you load tested it? Why not just get a new car battery and see if that fixes your problem?

 

I haven't had it load tested but it has never failed to start the car when it was 0°F outside a few months ago. I am not in the habit of replacing things *****-nilly and throwing money at a problem. I prefer to know what is wrong, testing to be sure that is correct and then repairing what needs to be fixed.

12.1V is acceptable and is roughly 50% charged. I topped it up but haven't checked it today.

I can't know for sure that the fast clock and the low battery are related until I have more data.

 

These car clocks, like battery operated watches, are not affected by the battery's voltage until it drops below a defined threshold, then the clock (or watch) just stops operating. In the case of a battery operated watch, the watch will keep excellent time throughout the battery's life until the day when the voltage drops below the defined threshold, then it just stops. The Lexus clock should work on the same basis.

I suspect the Lexus clock works off just a fraction of the car's 12 volt system - possibly 5 volts, and is regulated tightly with a Zener diode circuit. Therefore, unless a time-based component (e.g. time-based crystal) failed or some voltage regulator component (e.g. Zener diode or supply or load resistor) failed, it is doubtful the accuracy of the Lexus clock would be influenced by the car's 12 volt system even it it fluctuated drastically by many volts.

It sounds like it's probably a component failure (within the clock) to me...

 

New GS clock is controlled by GPS so no more buttons, except for Daylight Saving Time. That u still need to change manually from the Nav screen.

 

I'd keep an eye for a K900 at the junk yard with this. This would make an excellent substitute.

 

Still holding good time after a three week stint in the future.

 

Damn those tiny little electronic components!

 

Same problem here. Lexus NX 2015. Running fine until now. But y’all have too much time on your hands. I’m just ignoring the problem.

 

No, we have less time with a fast clock.

I have the time and the troubleshooting skills to learn from a problem, figure out a solution or create a mitigating plan. I treat a fast clock the same as I would a leak in the sunroof or tire that keeps going low.