Help - OBD-II port power failure

[essmd]

I plugged in an apparently faulty phone charger using the OBD-II port 12 volt power, and now there is no power from that port anymore, despite thorough testing.

I presume there is a fuse for this, or possibly a reset to restore.

Anybody have a fix??? Tesla Tech support not able to provide info.

Could also use the fuse box locations (other than the frunk) and diagram if available.

Thanks

 

[essmd]

So nobody ???

Oh well, I figured it out.

On my 2016 MX, the inside fuse box is to the right of the pedal has the 5 amp fuse, on the bottom of the row of fuses that is really hard to see, as you need to get your head right next to the brake pedal.

 

[essmd]

HOLY MOLY!!!...so when I called Tesla for support on this, I was transferred to the Dallas service center for "diagnostic support".

When I explained the situation, I was informed that the OBD port was not designed to charge a phone, or so a Tech was telling the girl on the phone.

Again I asked for help to replace the fuse, and the same response was given, as if to indicate that they were not going to support replacement of the fuse.

What the tech did not know is that the TPMS system is apparently on the same fuse, since that warning light was on solid and no numbers were provided, yet replacing the fuse resolved both issues.

I really wanted to push them to actually confirm that they would not provide service, but I just gave up, since I had resolved the issue.

That is yet another testament to the Apple-like control that Tesla maintains over their products, telling me not to use the OBD port to for power and not providing assistance for a simple fuse replacement, and I predict if I pursued the need for service, they would have charged me.

Name another vehicle manufacturer that "hides" the fuse box and refuses to support the owner to replace a fuse if needed.

 

[MP3Mike]

But they even included a fuse puller in there for you from the looks of it...

 

[essmd]

Yes, in both fuse boxes.

But without have any diagram for the fuse locations, I had to literally test every fuse for continuity, but did suspect only those 10 amps and lower.

Also, for the fuses in the frunk, I initially tested using a 12v circuit tester grounded to the chassis, which worked for testing but also created multiple warnings of system failures on the dash, including the dreaded "Needs Service, contact the Service Center"

After a bit of a panic, I reset everything I knew how, but the warnings remained until I powered off the car, then restarted. Whew... only the TPMS remained an issue.

Also, the inside fuse by the :gas" pedal was behind a carpet panel which was difficult to remove, and replace.

So despite the provided fuse pullers, they do not make it easy to access
.

 

[chillaban]

FWIW both my Audis and my previous BMW had a blurb in the manual about how the OBD II port is not an accessory port and is for diagnostics only.

I've never tried to short it to see what the service center says, but people who use coding cables and brick their car do pay out of warranty to service it.


It was pretty bad on my BMW ActiveHybrid 3 — OBD accessories keep the ECU powered on, and that will drain the 12V battery after 1-2 days.

 

[essmd]

FWIW both my Audis and my previous BMW had a blurb in the manual about how the OBD II port is not an accessory port and is for diagnostics only.

I.

I understand if my error would have resulted in a cost to replace a single fuse, if at a reasonable rate.

Had I initially called to claim my TPMS was an issue, they easily would have replaced for no cost, provided they did not ask if I used the OBD or if they did and I was not honest about it.

But the complete non-support for the owner to replace a fuse is ridiculous. If I had known this prior to purchase, of course that would not have swayed my decision, but again I am not aware of any other manufacturer that restricts fuse access.

What is a fair cost to non-warranty replace a fuse by a dealership? $150 / hour???

The longer one owns a Tesla, the more revealing of their quirks and deficiencies.

 

[Waldek]

Thank you so much for the input it just happened to me... and I called Tesla Support they have not told me where fuse might be located... they instead referred it local service and they said they will contact me within 24-48 hours... so I went to google and found your post thank you so much... need to open up the inside fuse box somehow and replace this fuse. I was using my OBD port to power BlackVue dashboard cameras and I just blew my fuse

 

[Waldek]

oh boy... it was hell of job to get this fuse replaced! geeez... hard to remove this piece of carpet on this plastic panel to get access and access to the fuse is real hard too... I impressed you were able to figure out which fuse was blown! If not your feedback I wouldn't be able to get this done lol! I am all set and everything is back up working fine thanks a lot! I forgot to put fuse puller back in spot and closed all already... *sugar*... anyway not opening this anymore I am going to just stick the fuse puller under the plastic piece just in case

 

[essmd]

oh boy... it was hell of job to get this fuse replaced! geeez... hard to remove this piece of carpet on this plastic panel to get access and access to the fuse is real hard too... I impressed you were able to figure out which fuse was blown! If not your feedback I wouldn't be able to get this done lol! I am all set and everything is back up working fine thanks a lot! I forgot to put fuse puller back in spot and closed all already... *sugar*... anyway not opening this anymore I am going to just stick the fuse puller under the plastic piece just in case

Wow, thanks for the feedback.I am so happy my hours of research, sweat and aggravation helped us both out, hopefully others in the future.

I am still pissed about my Service Center not willing to help out, but if I persisted they may have done something, but it really sounded like since they do not support the use of the OBD port for power, so support ended there since no need apparent need to replace fuse, short of paying them to replace a 5 amp fuse at $200+ / hour.

Putting back the carpet panel alone took me 30 minutes, trying not to break clips or anything, but I am sure my technique was not per the service manual.

My head was pressing into the brake pedal to see the actual fuse space (before I grabbed a mirror), which was forcing the door to close on my legs... it was like I was on Candid Camera.

Curious, did you notice your TMPS warning light on during the fuse failure, or was it just coincidental on my car, given all the other warnings I caused during my testing?

 

[Waldek]

Wow, thanks for the feedback.I am so happy my hours of research, sweat and aggravation helped us both out, hopefully others in the future.

I am still pissed about my Service Center not willing to help out, but if I persisted they may have done something, but it really sounded like since they do not support the use of the OBD port for power, so support ended there since no need apparent need to replace fuse, short of paying them to replace a 5 amp fuse at $200+ / hour.

Putting back the carpet panel alone took me 30 minutes, trying not to break clips or anything, but I am sure my technique was not per the service manual.

My head was pressing into the brake pedal to see the actual fuse space (before I grabbed a mirror), which was forcing the door to close on my legs... it was like I was on Candid Camera.

Curious, did you notice your TMPS warning light on during the fuse failure, or was it just coincidental on my car, given all the other warnings I caused during my testing?

yeah... it was same tricky for me to get it done.... I used 2 iphones - one as a flashlight and second one as a mirror lol

I put however 10 amps fuse in place of 5.... they did not have 5 ams fuses at Autozone

yeah I had same exact symptoms for TPMS first amber light flashing and then solid amber. No TMPS reading a tall for any tire.... it all went back to normal after replacing the fuse.

yeah you saved me lots of time! thanks a bunch, I owe you at least a beer or two! it was still uneasy thing to replace... I think I broke one clip while trying to get this carpet piece back in place.... I think that Tesla people have problems mounting this one too as one of clips was already smashed after I carefully took out... it looked like someone did not put it correct way and tried to push it in...

 

[tizio]

So nobody ???

Oh well, I figured it out.
...
View attachment 222517

I'm having trouble getting to this fuse box. Did you have to pull the center console first? Any other tips you can share would be great.

 

[Waldek]

I'm having trouble getting to this fuse box. Did you have to pull the center console first? Any other tips you can share would be great.

it is really hard to pull this piece of carpet... I was able to remove it from the bottom from the floor side... there is a way to pull it and I tried to pull down and out... and it came off the clips... the trick is there is one clip close to the tablet that holds carpet with console piece... but I was able to get out by puling the side of console a bit and carpet... the whole thing is very tricky to take it out and it is even much harder to put it back in place...

 

[Waldek]

no other tips as just be careful and try to get feel of each side of the opening and try to feel where it holds and pull gently to get clips off...

 

[tizio]

Thanks for the tips Waldek! I'll give it another shot later tonight.

 

[BrettS]

I put however 10 amps fuse in place of 5.... they did not have 5 ams fuses at Autozone

For what it's worth, this is a very bad idea. The wire connected to that fuse can only support 5 amps. If something tries to draw more than 5 amps then the fuse blows to protect the wire. By putting a 10 amp fuse in there you are allowing more than 5 amps on that circuit, running the risk that a wire may overheat and catch fire or melt and break or short against something, and both situations could cause many thousands of dollars in damage.

 

[essmd]

Thanks for the tips Waldek! I'll give it another shot later tonight.

I actually loosened up the entire center console side panel, all the way back to the seatbelt insert. I know it looks like a single console piece, but the side panel does have clips all the way back,

Once you loosen but not remove this, then the carpet panel is easier, but by no means easy to remove.

Replacing the carpet piece was just as difficult, small movements to get it back into place.

 

[essmd]

For what it's worth, this is a very bad idea. The wire connected to that fuse can only support 5 amps. If something tries to draw more than 5 amps then the fuse blows to protect the wire. By putting a 10 amp fuse in there you are allowing more than 5 amps on that circuit, running the risk that a wire may overheat and catch fire or melt and break or short against something, and both situations could cause many thousands of dollars in damage.

Sorry, but I disagree, it's not necessarily the wire protected by the fuse in automotive accessory applications, but the device on the circuit. All that is on that line is the TPMS sensor and the OBD-II port. I put in a 7.5 amp fuse and power the TPMS, a phone charger, and a dashcam for a week now, I really doubt I am exceeding the flammability of the wire.

For the sake of science, and using Wire Capacity Chart it shows that for a short run wire, for 12v 22g handles 5, 20g - 7.5A; 18g - 10A, 16g -13A, etc.

Your point is significant if they use less than 20g wire for the circuit and 10 full amps are being pushed through, which may be the case... but mostly not

I have spliced up enough automotive wires to know that rarely do they use less than 20g wire, but then again this is Tesla.

 

[4SUPER9]

@essmd, thank you for posting this. It took me awhile to figure out what was going on here. I had a bird's nest of wires under my driver's dash for my radar and a GPS extender, and as I moved them around, I lost power. I thought at first it was one of my connectors, but eventually figured out it was by OBD port. I found this thread with a list of fuse boxes and could not figure it out until I found your posts above. For the record, it is fuse #219, listed as "Glove Box Light, Diagnostics". In case the fuse boxes change again, don't look for "OBD", but look for "Diagnostics".

 

[Akikiki]

essmd and 4super9, particularly thank you essmd for this info. You have not by any stretch heard the end of this. Every time someone else blows the fuse they are going to see your great work and thank you. So thanks again. And for 4super9, you confirmed what I was going to suggest. I have a '17 S and when through the same things. The fuse and fuse panel is in a different location, but YES, the same 5 amp fuse feeds the OBD II port, the TPMS and the glove box light. So, people if you suspect the OBD II port is not working, look at your glove box light - if its not on, its that fuse. Good work essmd and 4super9. Its the same S or X.