No power to front USB

[SFB]

Im sure there are other that has had this happen, temp fix is disconnect neg. battery cable for about 30 sec so the main computer resets. However, frequency of the no power has increased. I'm thinking it only needs to have the software re flashed. Has this been the fix?

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[FunInTheSun]

Check the consumption of what are you plugging into it. The front USB ports supply data AND power, and they may have a strict(er) implementation of the USB Standards. USB 1.0 and 2.0 ports have a standard max allowable power is 2.5 watts, (5 Volts at 500 mA, or 1/2 Amp) and they may or may not shut themselves down if this limit is exceeded. According to strict USB standards, anything more than 100 mA is supposed to be "negotiated" with the host. It can get complicated*, but the bottom line is:

it may be shutting off due to excessive power draw. Try plugging the device into the rear USB points, as they are "dumb" charge-only points and may not care as much.

I keep a USB thumb drive plugged into my ports, so I have never pushed their limits. For charging duty, I have a "dumb" cigarette lighter plug charger that I use for charging my phone while I stream tunes from the USB.

* Geeky details: https://superuser.com/questions/690074/what-is-the-power-output-of-a-usb-port

 

[SFB]

Only my phone, usually listening to Podcasts, has worked fine till within the last year. It always happens after I've shut down and then the next restart no power. I've tried the back port, also no power

 

[btsmith52]

Replace your cable if you haven't already. Use a quality one. An intermittent short could cause it. Cables fail a lot in cars due to the frequent movement.

 

[airline tech]

I agree try another cable, the APIM is tripping off power to the USB ports, if it senses power issues to protect the system.
You might also ensure your Sync is updated to latest version.
If you have FORscan or Scanner that can read (B) Body codes, you will most likely see a code in memory. Clear code and perform APIM Module Reset. This will pin-point down your issue. Most likely short to ground using code you have you can use that for Pin-Point Troubleshooting, might just be a loose connection as well

 

[Kawffin]

I agree try another cable, the APIM is tripping off power to the USB ports, if it senses power issues to protect the system.
You might also ensure your Sync is updated to latest version.
If you have FORscan or Scanner that can read (B) Body codes, you will most likely see a code in memory. Clear code and perform APIM Module Reset. This will pin-point down your issue. Most likely short to ground using code you have you can use that for Pin-Point Troubleshooting, might just be a loose connection as well

Check your fuses . Mine was cutting in and out, ended up being a loose fuse.

 

[FunInTheSun]

Replace your cable if you haven't already. Use a quality one. An intermittent short could cause it. Cables fail a lot in cars due to the frequent movement.

+1 for this.

If the cable shorts, it will draw excessive current and trip the port protection. Doesn't have to be a constant short. Just long enough to trigger the protection.

 

[SFB]

Replace your cable if you haven't already. Use a quality one. An intermittent short could cause it. Cables fail a lot in cars due to the frequent movement.

Yea, did that too, thought I had solved it, but no, has done it again. Well I think its a software bug, similar to your personal PC when you have to reboot to clear memory, which is why removing ground cable will solve it temporarily.

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