The mystery deepens.

This morning I took the RX out for a quick errand. The temperature was around 20*F and when I initially started the car there was no shift system malfunction message (and I didn't expect one at this temperature). Restarted the car after it sat for about 15 minutes at my destination and I immediately got the shift system malfunction message. Every time I cleared the message it returned within a second or two.

So two "firsts" today:
1. First time I have seen this message at temperatures above about 10*F.
2. First time that the message didn't appear on the first startup of the day but did on the second start. Previously I have only seen this message on the first start of the day and never on subsequent starts.

Seems to me that this kind of shoots down the theory of low battery voltage causing this message. But I just saw these two related topics links:

Shift malfunction error - ClubLexus - Lexus Forum Discussion
Shift system malfunction please see owner’s manual - ClubLexus - Lexus Forum Discussion

I don't know why I never noticed these links before but at any rate, while I don't know if there is any correlation between these messages on the NX and the RX, it seems quite possible to me. I plan on visiting my local dealer in the coming week and showing the service advisor this: Shift System Error. Perhaps this TSB needs to be expanded to include the RX 350's. I have no idea how to get this ball rolling but I will see what he has to say about it.

 

Possible, they use the same shifter mechanism.

 

I did take my 2023 Lexus NX350 (non-hybrid) into the dealership for this issue. It happened “once” (so far) when starting the car and I didn’t even have a chance to move the gear shift out of Park.

At all other times (2 so far) it occurred at the very beginning and not while driving away.

All in frigid temperatures.

The Customer Service Rep said he has seen this recently and suggested it may need a S/W update.

The service mechanic verified that the car already had the latest S/W update. He could not find a cause.

The CSR said he will file some sort of report with Lexus to register the issue hoping to get further guidance.

Sure hope it doesn’t happen during driving. As I see it, it’s a “safety recall” and not just a Technical Service Bulletin IF they have a solution to fix it!

 

I had the message pop up a few days ago for the first time, and yes, it was zero degrees out. After I drove a bit it disappeared as I hoped it would.
By coincidence we just had our software update yesterday, so we'll see what happens.

Of bigger concern now (and this is not a Lexus problem per se) is that we have had a slow motion four day snow storm with low temps, and the car is entirely encased in frozen slush, so none of the sensors work and you really can't just dust them off. Causes a lot of lights to flash on the dash, which is at least a sign of Christmas I suppose.

Waiting for a warmer day, an end to the snow, and a visit to the car wash...

 

So I went to the dealer yesterday and had a nice conversation with a service advisor about this issue. He is quite knowledgeable about these cars and I trust/like him.

He was familiar with the TSB for the certain NX year/VIN's that I showed him. He first checked that there was no recent TSB issued for the RX's; there were none (as we both expected). We both agreed that it is most likely a software glitch given that the car operates normally while the message is displayed. We talked about the possibility of low battery voltage being the culprit as most of the cases that he is aware of have been on hybrid models that are not driven much. Since my car is not a hybrid and I drive it almost daily, I don't fall into this category, but a faulty battery is still not out of the question.

The bottom line (IMHO) is nobody knows what is triggering this message and until someone can pull an active code, nothing is going to happen. I have a standing invitation to bring my car into the dealership whenever I see this message again so that the techs can try to get this code. I plan on doing exactly this and would encourage everyone getting this message to do the same thing.

 

I live in southern Ontario and got the shift system malfunction message once or twice last winter, and now this winter almost every morning I don't use auto start. I have also noticed a perceivable hesitation when shifting out of reverse into drive, after exiting my driveway. Took it into the dealer and they did not really want to do anything about the warning message but did run a code scan regarding the shift hesitation. Naturally they did not find anything. Service advisor told me they are seeing numerous complaints about the shift system warning, but without a service bulletin from corporate Toyota telling them what to fix they can't do anything. This is the third problem I have had with my 2023 RX to date. I have had all the door handles replaced because they did not work in the cold and the body control module replaced because the nav stopped working. So far the car has been in the shop for over 6 weeks total and I have only owned it for two years! I am so glad I leased it and can walk away from this nightmare in a year.

 

Started the car this morning and immediately got the "Shift System Malfunction" message so off to the dealer I went. They had the chance to actually see the message and check for codes; there were none.

I had an informative conversation with my service advisor about this issue and here are my takeaways:

1) Being that there is no code set, there is no cause for alarm for us owners, just a software glitch. This is backed up IMHO in the fact that the car performs flawlessly.
2) The VVT software update that I had in late November also had a "secondary" or additional update (don't know what else to call it) that was supposed to address this issue. Apparently, it is quite common and a very well-known issue.
3) Despite the lack of a code, I do not regret my time spent at the dealer as my complaint/issue helps push Lexus for a fix.
4) Battery voltage was 14.4V so low battery voltage has been ruled out.

This is all that I have for now. But I encourage everyone that is getting this message to please see your dealer. As the saying goes, "The squeaky wheel gets the grease".

 

Big cold front coming into the US next week, I suspect a lot more posts about this. They clearly have a software issue with the self-test routine on the gearbox.

 

yep we'll be well below zero on Monday night. From how I interpret these posts, no one is actually having a driving problem, right? i.e. the message pops up as it did for me, but ignoring it seems to work fine.

 

Correct. This is just a software glitch.

 

My wife's RX 350 (Gas) displayed the warning this AM on her way to a medical appointment. Temp was 19F. Car drove fine. She texted me as she hadn't seen it before. Once she was done with the appointment and restarted the car to meet a friend for lunch it had cleared.

 

This happen to me for first time, I really think it has to due with low battery. As I was out of town and car sat for over week in very cold temperatures. It came on, then without even shutting off it just disappeared.
This was 3 weeks ago, still cold but being driven daily and no issues again with message.

 

This is a follow-up to my original post.

Yes, it happens in freezing temperatures.

Yes, the warning continues during a short car trip ( E.g. to a nearby shopping mall)

Yes, a second car trip (E.g. drive home from the mall), the shift system malfunction warning message does not reappear.

Yes, the dealer diagnostic did not report a problem. It’s hard to reproduce it
at the dealer unless you leave the car overnight on their lot in freezing temperatures so that they can see the warning message first hand on a first startup with diagnostic equipment already attached and recording.

Yes, I already had the latest S/W upgrade installed.

My theory is that, under very cold conditions, electronics respond more slowly. (E.g. A monitor display may lag a bit.) Pressing the Start button initiates a series of circuits. The shift system sensor connection is frozen and fails to register within a specified time limit. All within milliseconds!

Thus, the warning message pops up. Benign but frustrating nonetheless.

 

Fix may be on the way.
.
I had this intermittent issue last winter on our 2023 NX 350. Similar conditions to most of you - after not operating for a few days and in colder weather, the car would display "shift system malfunction" after starting. Shutting the vehicle after warm up and restarting within a few hours, the display would not show the malfunction.

I took it to the dealer last winter. The malfuction was not present on the display when I brought it in, but I showed them a photo. They did find fault codes in the diagnostics unit. They reset the fault codes and said they could not take corrective action unless the malfunction was on the display.

I did not have the malfuction displayed all summer. In the fall, after long periods without operation it did appear a couple time. Now CT is in the middle of winter and it has got cold - the malfuction display is reappearing. So I schedules an early morning service appoint on a day forecasted to have low overnight temperatures and after not driving for two days. On the morning of the service appointment, the malfuction display appeared. When I arrived at the dealership I did not shut the vehicle off, and had the service adviser come out to see it. She attempted to have a technician come out, but determine that was not necessary. Coincidently, the regional service representative was going to be at the dealer that day.

When I picked up the vehicle, the service adviser had been told by the regional service manager that Lexus was aware of this issue and had been working on a solution. In fact, the regional service manager authorized the technician to perform a software update to the gear control module ahead of its release. So it appears a service bulletin is on its way to reprogramming the gear control module and correct this issue.

During the thorough troubleshooting of the gear system malfunction, they also found an open cell in the battery - replaced the battery under warranty. They also implemented the ECU software update to correct the cam shaft pin lock issue. Filled up the gas tank.

After after two cold days with operating the car, I did not have the shift system malfunction on the display after starting. Its been a couple weeks and we have not seen the malfuction display reappear. I was expecting this intermittent shift system malfuction would continue to be a gremlin that would not be corrected, but I am pleased with the correction and service I received at the dealer.

 

Wife's car sat since Monday. It's been cold outside but only down to about 38 - 42F in the garage. Started it up today to run down to Detroit for a play. The "Shift Malfunction" alert showed up as we pulled out of the driveway. After driving for an hour and leaving the car for 3 1/2 hours, fired up the car for the drive home. The malfunction didn't reoccur. The times it's happened to my wife's car have always been when it was cold outside and the car had sat for 3 -5 days.