On a 2023 ES 350, traffic flow for major roads (interstates, highways, etc.) should be color coded as green (free flowing), yellow (slowing traffic) and red (very slow to stopped). For the past 2 months, this display has been mostly absent from my car. I know the car is receiving real time traffic information; if I select navigation and proceed to a destination(i.e., home), the selected route (typically a blue stripe) will change color when traffic on that selected route slows or stops.

I had the system reset at the Lexus dealer but that did not solve the problem. For a day, I had a loaner ES 350 from the dealer, and it exhibited the exact same behavior. That makes it highly likely to be a vehicle software problem that the dealer is unable to do anything about.

Has anyone had the same issues as me? I live in Southern California; the dealer was Lexus of Riverside (60 or so miles east of Los Angeles). If anyone has a solution, please post it.

 

This is just another example of the quality and accuracy of the Lexus nav system. On my 2020 which is different than yours a nav guidance tried to carry me 45 minutes out of the way because the route still showed solid red from a wreck that was cleared 3 hours earlier. I immediately caught it and used android auto and have never used the onboard nav for guidance again. As I have said in previous posts I was told when I purchased my 2001 LS430 Ul which I still have that Lexus nav is there weak point and still is. I think this is why also with a lot of pressure we now have alternative such as android auto.

 

Provided the Data Communication Module (DCM) has a (cellular) network connection, the Lexus Interface Cloud Navigation system updates traffic data only when searching for a new destination; while progressing along an active route guidance; or when the vehicle enters a new area (unspecified what constitutes a new area). From the (US) Lexus support article LEXUS INTERFACE DRIVE CONNECT CLOUD NAVIGATION:

 

The traffic data visible on my 2020 uses the HD radio as per manual and I don't think it ever used the cloud. The new system may use the cloud but you can check the manual to be sure. If the new system also uses the HD radio it could be there is no HD signal in that area. You can check by just trying to tune in an HD channel.

 

The 2022 and previous Dynamic Navigation system sourced traffic and weather information from both or just HD Radio. (There's a setting for that.) From the 2019 to 2022 Lexus ES300H, ES350 Navigation and Multimedia System Owner's Manuals (page number varies in the range between 180 to 184 depending upon model year version) "6-1. Information display" subchapter, "Data services settings*" section:
The "new" system only uses the DCM and only for traffic data. From page 109 for both the 2023 (title is slightly different) and 2024 LEXUS ES250, ES350, ES300H MULTIMEDIA OWNER'S MANUAL:

 

Ok I had forgotten mine can use both as I don't use it because of the inaccuracy. So now it is a totally subscription service.

 

Sounds good in theory. In actual practice the “latest” route info was frequently woefully outdated.

 

This is my theory on what is going on ..
The method(s) controlling the Map Display (Map Display is one of the 5 displays that are visible on the ES 350 screen) do not display Traffic Flow until the communication module establishes a connection to the traffic flow provider (it's over the air). Upon making the connection, the software should issue an event that the Map DIsplay module(s) should subscribe to.

I am hypothesizing that the Map Display module(s) do not implement (for what ever reason) the reception of that event.

Why do I think that is so?

Every time I start up the car during the day when the car is parked in my garage, the Map Display goes into Nighttime mode (not alot of light in the garage). I don't see traffic flow while I'm in the garage. I back out of the garage (into daylight conditions) and 5-10 seconds later, the display switches, as it is supposed to, to daytime mode. When that happens, lo and behold, I see the traffic flow indicators on major roads.

If I go somewhere and park outside, the Map Display starts up in daytime mode if I start driving during the day. In that case, the Map Display never changes mode and I never see the traffic flow.

In that case, if I manually change the Map Display to Nighttime mode (and then swap back to Daytime mode) lo and behold, I see traffic flow indicators on the major roads.

The Map Display software has a bug that needs to be fixed.

 

If you haven't done so already, please file a bug report with (US) Lexus. Go to the Contact Lexus web page, scroll to the bottom to find a "SEND MESSAGE" button, click on it to get a "WELCOME TO SUPPORT REQUEST!" web page, for US support click on the "CONTINUE" button to go to a "TOPIC DETAILS" web page with a "SELECT TOPIC" drop down menu, select "Multimedia Technology" from that menu to get a "SELECT SUBTOPIC" drop down menu, select "Navigation" for that second drop down menu which will result in a expansion to a fill out form for your VIN and 5000 maximum character comment field. (There's a provision for including image or video files if necessary.) After filling out that form, click the "NEXT" button to go to the "YOUR CONTACT INFORMATION" form web page. After filling out that form click on the "SUBMIT" button to submit it.

Based on my past experience in reporting issues to Lexus through the message contact form, Lexus does read and reply in a timely manner. The initial reply will be an automated "We got your message" acknowledgement e-mail. The next reply will be from an actual human with an individual message composed in a manner showing your message has been read, understood, and your specific issue is being addressed. For software/firmware issues/bugs, the response will probably be some form of "we confirm it, we've entered into the issue tracking database, and forwarded it to our <<responsible department>> for resolution".

 

Thanks for the suggestion. I filed a support request; it was acknowledged, and it is currently pending. I have been a software engineer for a very long time and this is clearly a software defect.