I liked your guess, so I took one of my cables and crimped it a tiny bit. It was enough to make it a little tricky to plug it into the upper port; definitely snug. Unfortunately, that didn't change the behavior.

Not sure a shim vs slight crimping would make a difference, but it sure seems tight when plugged in. (Same crimped cable works correctly in the lower port.)

 

This is for a pre Car Play model. My '23 does not have the mini plug like my older models. BTW, mine works fine since June of '23.

Edit: I stand corrected…I just checked my ‘23, and it does contain the mini jack port. Sorry for the misinformation. (BTW, my ports work fine. Don’t know the build date without taking another stroll to the garage, but it arrived in the US in July of ‘23.)

 

The image I posted previously was the result of googling for the part number given to me by the parts department. See below for the replacement part that was installed. The dealer would not give me the old part because it had to be tagged and returned to Lexus. New part behaves the same way as the old part did.

New part

 

My 2023 built in October 2023 has the mini plug and two USB ports. The upper USB is problematic.

 

I have a 2022 IS500 LE. I have used the top USB port since I got the car with no issues, used Anker cables as well. However, I noted that the problem never happened with my old phones, until now that I have the iPhone 15 Pro. I am using a Anker USB-A to USB-C braided cable and it acts up from time to time.

Using the bottom port, seems to work all the time, but this is annoying.

I ordered a higher end Anker Powerline II cable to see if this helps and will try cleaning the top port with compressed air.

 

I have the iPhone 15 Pro also. Just took my wife's iPhone 13 Mini out to the GX and put its charging cable in the upper USB port. It worked! This is becoming a technical challenge since the issue is now confined to a specific iPhone model plugged into a specific port.

Anybody else try two different models of iPhone in that upper port? Android?

 

Interesting to also find out what are the spec differences if any at all between the top and bottom ports. Does anyone know?

EDIT: I tried my Carlink Wireless Carplay adapter on the upper port and it no longer works like it used to. I have to use the bottom port. I also just tried the new Anker Powerline II cable USB A to USB C and same issue.

I am worried that overtime, both ports won't work anymore. This is weird, maybe the car needs a software update.

 

I tried a Google Pixel 7 Pro, and it worked correctly with Android Auto in both the top and bottom ports.

Same cable with my primary iPhone 15 Pro Max does not work. Nor does a wireless CarPlay adapter. It seems like something wrong with iPhone 15 Pro/CarPlay specifically.

 

Interesting—maybe the charging requirements for the 15 Pro and maybe 15 Pro Max are unusual enough that they are messing with the USB functionality of different Lexus models, not just GX.

 

I purchased two more cables; Belkin and Amazon Basics. The Belkin is a thicker cable and the Amazon Basics is a skinny one. Plugged my iPhone 15 Pro in the top usb port and started with Belkin. It cycled a dozen times and settled down, CONNECTED. Next I tried the Amazon skinny cable. It cycled six times and CONNECTED.

This has not been a proper experiment by any means. At best, it's a work-around. Previously I was probably not patient enough to wait and let the issue play itself out (no pun intended). So it appears that both ports are usable, and that if you want instant connectivity for CarPlay, use the bottom usb port. Good luck to all and please let me know if you see similar behavior in your vehicles and the iPhone 15 for those who have it.

 

New member. Bought mine yesterday. Saw this thread and tried my front ports with my iPhone 15 Pro Max. Sure enough, the top one doesn't reliably work. 10/23 date of manufacture.

Now for the fun part...I'm a USB engineer, and not to dox myself too much, but I helped write the specification and have supported this interface professionally since inception. It's kinda like my baby. Anyway, as a good (?) USB engineer I of course had some old interface analysis hardware laying around at home so I hooked it up and took a peek at what's happening.

TLDR: this looks like a power problem exacerbated by the inclusion of Type-C on the new iPhones.

In the olden days, USB Type-A connectors (these are the ones in the GX) were expected to always supply 5V (+/- .25V) @ 500mA (minimum). As time went on the spec was changed to permit up to 5.5V volts which provided a little bit of headroom for very long cables (the longer the cable, the greater the voltage drop from end-to-end). The GX is using the old standard and provides ~5V all the time. It also has very long cables. You can see where this is going...

With the introduction of Type-C, the same connector can provide a huge array of different voltage and current profiles, but in order to do so safely it has to "negotiate" with the attached device.In most cases, this requires a special chip that helps both end of the link arrive at the highest common profile and THEN the power is turned on. Makes sense if you think about it...a laptop and a cell phone have very different powering requirements so the resulting negotiation would also be very different. Don't feed 20V to a device that can only handle 5V!

Now that we have the power part understood, there is a bit of an added wrinkle in play here: CarPlay. In the USB world there are Hosts and Devices. The Host is the one running the show and the Device pretty much just does what it's told. In this relationship the HOST is also the one supplying the power. CarPlay turns this around a bit in that your phone is the Host, it runs the show, but obviously we also want to charge our phone from the car so the power profile is reversed. The phone is still the boss, but it is getting power from the car rather than the other way around. This also takes some negotiation which is handled by the CarPlay protocol in that when the phone is first plugged in, it's a Device initially, it then tells the Host (the GX) "Hey, I want to be the boss now, but you keep providing the power" so the two do what's called a role-swap. Both sides are now happy. GX driving power to the phone, phone driving data (CarPlay) to the GX.

Sorry, I know this is long, but the problem is that the GX power delivery to the top socket is marginal for the Type-C enabled iPhones. The iPhone gets plugged in and the USB voltage "droops" below the minimum permitted which causes the GX to sense this, turn it off, and then back on again. I see it on my analyzer. This in turn causes the phone to restart both Type-C and CarPlay negotiation and the cycle may/may-not repeat. I do not see this getting fixed by Lexus as the cable length and power delivery can't be (practically) changed. Apple may be able to provide an update that reduces the inrush current to the Type-C controller, which would help prevent the voltage droop, but I wouldn't hold my breath as they are operating within today's specification. A "new" GX USB insert may temporarily fix the problem, but it will reappear as the connectors age.

Suggested solutions:
- Only use the bottom socket. Duh.
- Use wireless CarPlay with a 3rd party adapter. I'm betting the top socket works fine in this case because no Type-C negotiation is required and the in-rush current is probably more tightly regulated. This is likely what I will do as the charging current provided by the GX is woefully small for today's phones anyway. No sense in owning a phone that can charge at 20+ watts and then plugging it into a socket that can only supply 2.5 watts (5V @ 500mA).
- Try different cables. The shorter the better. This is unlikely to be a permanent solution.

If the engineers at Lexus/Toyota are reading this: You should have cranked your VBUS capacitance on both ports in ~2014. The spec says "minimum 120uF for Hosts", but the spec also says your topology shouldn't permit in-rush current induced droop of < 4.75V at the connector. If you can't make the latter work, you needed to increase the former.

 

Wow, this is a great response. Couple things:

1. I’ve tried three USB-A “native” wireless CarPlay adapters (i.e., a USB-A plug, not an adapter), and they all behave the same way: power cycling, never working. They all work in the lower port.

2. I’ve tried a Google Pixel 7 Pro—which is USB-C—and it works in the upper port with Android Auto. Definitely seems like a CarPlay/Apple thing.

 

I see a Samsung in this thread with AA that does same thing. Not sure if it's Type-C, but I bet it is. Definitely not CarPlay.
I tried an iPhone 12. No problem. CarPlay with no Type-C.
I tried an iPhone XR. No problem. CarPlay with no Type-C
I tried an iPhone 13 Pro Max. No problem. CarPlay with no Type-C.

Sooo...facts as I understand them today:
- CarPlay in itself is fine.
- AA in itself is fine.
- Add Type-C to either of above and you may have a problem.

If all above still true, then we are back to Type-C being the only problematic variable. This aligns with my inrush current/VBUS droops hypothesis.

PS: Excluding your CarPlay adapter for now to reduce the variable-set. I have one on the way.

 

More fun Type-C.

Because the power delivery (PD) is negotiated, the PD chip inside the consumer (the phone in our case) needs power before it can ask for power. If your phone is 100% dead, how can the PD chip ask for power to charge it? Chicken and Egg. The spec addresses this. The PD chips are designed to provide basic functionality at the guaranteed power profile: every USB Host on earth must provide at least 5V @ 500mA. This is enough for the PD chip to operate...but it's not free. With the addition of the TypeC controller, we've added another power consumer to the USB and the GX can't supply enough.

So it goes like this:
1) Phone is connected. PD controller begins operation. It is consuming USB power. Phone is running on battery.
2) PD controller signals Phone "negotiation complete, you can consume 2.5W USB power now".
3) Phone switches from battery to USB power. Now both PD and phone are powered by USB.
4) This instantaneous spike in current consumption causes the USB voltage to droop. GX sees this, thinks there is a short circuit (or other problem), and power cycles the USB port.
5) GOTO #1

I don't have my fancy protocol analyzer with me, but I do have my power analyzer, and can absolutely see the port power being turned on and off by the GX. It should always be on unless there's a problem. The GX sees a problem, and it's electrical.

 

/\ Outstanding set of posts, man. People who know what they are doing and communicate well are an increasingly rare treasure. Welcome to the 'hood!

Mark