Have you checked or change the fuse?

 

I wonder if perhaps you are encountering some sort of current draw protection mechanism (i mean something other than the binary one-shot mechanism of the fuse). Is it possible for you to spread your load across two different circuits and see if that makes a difference?

 

I wonder if perhaps you are encountered some sort of current draw protection mechanism (i mean something other than the binary one-shot mechanism of the fuse). Is it possible for you to spread your load across two different circuits and see if that makes a difference?

That’s what I was thinking as well, but why would this happen if both USB ports are standard?

I would assume that Porsche’s USB ports should be designed to handle typical charging loads, especially since one is just charging a phone and the other a small dashcam. Neither of these should be drawing excessive current.

Do you think the system is being overly sensitive to current draw, or could it be a software issue where the power management system momentarily cuts power?

 

Is this with the engine running? And is the battery fully charged / car driven frequently?

I received a dash message a few weeks ago indicating something like "accessories have been turned off to conserve battery charge". Don't quote that exactly. It occurred after I hadn't driven the car much for a few weeks. The message went off after the car was started, but it still took longer than usual for my wireless CarPlay dongle to connect with the car.

 

Good questions!

Yes, this happens with the engine running, so I wouldn’t expect it to be a battery-saving issue. My car is also driven regularly, and I haven’t seen any low battery warnings or messages like the one you described.

If the system was cutting power due to battery conservation, I would expect some kind of warning on the dash. But in my case, the USB ports just momentarily lose power and then restore it, without any notifications.

I wonder if it’s some kind of overcurrent protection or software glitch in the power management system.

Has anyone else experienced something similar?

Thanks for the input!

 

Hi everyone,

Following up on my USB power loss issue in my 2021 Porsche 718 GTS 4.0, I wanted to share more details about the devices I’m using and see if this could be a power draw issue.

Devices Connected:

• OnePlus 13 (connected to the USB port inside the armrest)
• Garmin Dash Cam Mini 3 (connected to the USB port inside the glovebox)

Power Consumption Estimates:

• The OnePlus 13 supports fast charging up to 100W, but when connected to a standard USB port, it should draw much less.
• The Garmin Dash Cam Mini 3 operates at around 1.2W - 1.8W, meaning it draws approximately 0.24A - 0.36A at 5V.

The Issue:
Occasionally, both USB ports momentarily lose power, causing my phone to stop charging and my dashcam to turn off for a few seconds. The power then comes back on as if nothing happened.

Could this be a case of overcurrent protection triggering due to the combined power draw? I would assume Porsche's USB ports can handle this load, but maybe there’s a limit I’m exceeding?

Has anyone else experienced something similar or knows the exact power limits for the 718’s USB ports?

Thanks in advance!

 

@TPE has some good questions. IMO, if the temporary/momentary power loss to the referenced USB ports is occurring when everything is powerup and in steady state, and the electrical system is otherwise in good health, then this sounds like either a loose connector, a bad module controlling the effected USB ports, or a fault (short) to some extent.

• How frequently does it occur and is there any commonalty about when it does happen?
• Does it occur only when both devices are plugged in, or can it occur with only one device plugged in?
  • If only one device, then does the problem occur no matter which port is used? In other words, does the problem travel with the device or stay with a port?
  • Try each device individually as maybe only one of the two devices is a bad actor.
• Does it occur at all if neither device is plugged in?
  • This can be determined by using a cheap little device that will plug into a USB port and indicate the voltage.
• Maybe one of the devices has a short that causes a possibly common power supply to clamp its output. One of the cables might have an internal short.

If the problem never occurs when only one device is plugged in, then maybe the power supply is just appropriately responding to one of the devices that might be misbehaving with a greedy electrical power desire, not enough by itself to cause a problem, but too much if another USB port is also supplying power.

 

You could always try putting one of those current / voltage measuring tools inline with each of your devices (I mean one at a time) and see if it shows weird voltage or current draw values at the time you see your "brownout" condition. That might at least rule out one of your devices behaving in a not-nice way.

For reference, I have this Klein Tools one:

 

You might want to try putting one of the devices on a cigarette lighter port with a USB charger. Monitor both devices and see if both or just one might go off. That'll tell you whether the on-board USB port is the problem, or the accessory power glitches.

 

If I'm remembering right and they didn't upgrade them throughout the model years, the usb ports are low amp ports. Something like 0.5 or 1.3 amps, not standard 2.1 or higher. That's why I have to use a y cable with a charger in the cigarette lighter to run Android Auto and charge my phone.

 

Thanks, that actually makes a lot of sense.

If the USB ports in the 718 series are indeed limited to 0.5A–1.3A, that would explain why my OnePlus 13 might be overloading the port and causing the power cut.

You mentioned using a Y-cable with a charger in the cigarette lighter — could you explain a bit more how that setup works in your case?
Are you using the data connection from the USB port and pulling power separately from the 12V charger?
Would love to see a picture or link to the type of cable you’re using, if possible.

Thanks again — this might be exactly what I need!

 

Hi everyone,

Quick update on my USB power issue in my 2021 Porsche 718 GTS 4.0:

I’ve separated the dash cam from the USB glovebox port and connected it to a 12V cigarette socket via adapter, while keeping my OnePlus 13 connected to the armrest USB port.

Since doing that, the dash cam no longer shuts off — only the phone now disconnects intermittently, which makes it clear that the phone is triggering the power cut on its USB port.

Has anyone experienced something similar with Android phones (specifically OnePlus), or knows a workaround? Is there a setting or cable type that could help stabilize the connection?

Any help would be much appreciated!

 

Update on USB Power Loss Issue – OnePlus 13 & PCM (2021 Porsche 718 GTS 4.0)

Hi everyone,
Just wanted to share a quick update for anyone following this thread or facing similar USB power dropouts, especially Android users.

After experimenting with different setups, I found that enabling USB Debugging on my Android phone (OnePlus 13 in my case) significantly reduced the number of USB disconnects while using Android Auto.

🛠 Steps to Enable USB Debugging:

1. Go to Settings → About Phone
2. Tap Build Number 7 times to enable Developer Options
3. Go back to Settings → System → Developer Options
4. Toggle USB Debugging to ON

In addition, I went into the app settings and cleared the cache for the Android Auto app:

• Settings → Apps → Android Auto → Storage & cache → Clear Cache

🔍 These two changes seem to have improved connection stability quite a bit — my infotainment hasn’t been dropping out mid-drive as often as before.

Still testing this setup over a longer period, but I thought it might help someone else here struggling with similar USB behavior.

If anyone has additional tips — or knows the exact current limit per port on the 718 — I’d love to hear more.

Thanks again to everyone for the support in this thread!

 

Taking advantage of this thread… one of the warranty items I’m going to have dealer look at is that I haven’t had power in the center stack cig lighter for almost 3 years (new car warranty ends this November).

On one hand, I never use it, on the other, I guess like to have it available for that just in case need.

I think I tried changing fuses, but in the case I didn’t do the right one, can anyone confirm the fuse for this power outlet?

 

Sorry. Just saw this post. According to the attached, the fuse for the center console cigarette lighter is D9 in the passenger side fuse box.