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New Model S 75 UMC GEN2 issues.

enzo86

Member
Nov 24, 2017
28
11
NC
Hello,
I Just picked up my new MS75 on Saturday, and I have been having issues with the UMC. This is the new Gen 2 UMC that has a max of 32 amps.

https://www.tesla.com/sites/default...bile_connector_owners_manual_32_amp_en_US.pdf

The UMC will be green, I plug it into the car and the charge port turns red, and the UMC T flashes Red once. If i unplug the UMC and the car, then plug it back in, then it will charge, sometimes i have to go through this process a few times.

I looked up the single flash and it states:
"1 flash Ground fault. Electrical current is leaking through a potentially unsafe path. Unplug the Mobile Connector from the vehicle and then plug it back in. Try a different outlet. If the error persists, contact Tesla."

Whats Odd is if i plug in our clipper creek j1772 into the same outlet and use the J1772 adapter it has no issues. The UMC is using a 14-50 with #6 wire on a 50 AMP breaker, Installed by a licensed electrician.

Once the UMC starts charging i get 28mi/hr at 241v and 32Amps.

Any chance i have a bad G2 UMC ? Any Advice would be helpful.
 

gaswalla

Model S,3,X.. CT with Austin delivery
Sep 23, 2012
3,298
3,581
San Diego
It's not your car. It's either the umc or the electrical supply.
You can take the umc to the service center and they'll check it out - probably will take 15 minutes.
Hopefully it's the umc
 

enzo86

Member
Nov 24, 2017
28
11
NC
Have the electrician look at it again, Did you try the charger that came with the car? No one here can fix it.

What other UMC would I have used? I don't think it's an issue with the car and it's not an issue with the 14-50 since it works fine on our other Clipper creek. Ill have the SC take a look at the UMC and see whats up.
 

Xd85

Member
Oct 20, 2017
241
195
Central Ohio
Same as mine, delivered last week. Will update the results of SC “resculpting” the charge port. I was told preliminarily that the cable was fine when it did this.
 

enzo86

Member
Nov 24, 2017
28
11
NC
Same as mine, delivered last week. Will update the results of SC “resculpting” the charge port. I was told preliminarily that the cable was fine when it did this.
Maybe it's just a matter of putting a little more force into it when inserted.
 

fcharland

Member
Jun 18, 2013
70
50
Qc, Canada
Electrician here...

This error means there is a problem after the UMC's power contactor. So probably a bad crimp somewhere in the UMC.

If there was a problem with the wall socket, the UMC wouldn't glow green at first when it's plugged in without charging anything.

Replace the UMC, and you should be fine.
 

atkelvin2001

Member
Nov 6, 2017
19
11
Seattle, WA
I have the exact same problem for my new Model X I got on the 12-28. My guess is that the connection between the part connecting to my car and the other part connecting to the wall is not 100% attached because mine is hanging off the wall plug. So what I usually do is pull cable from the wall, detach the cables and the charger, then reattach them. It usually fixes the issue.
I thought I was the only one experience this ... but seems like it could be more wide spread ....
 
  • Informative
Reactions: GSP

Aw305

Member
Dec 23, 2017
7
2
New York
I had the same issues, my local tesla dealer gave me a gen 1 cable to bring home to try out, it works every time with no issues. the gen 2 cable has issues every time, I have to unplug and re plug it in at the outlet to make it work
 
  • Informative
Reactions: GSP

Need

Active Member
Nov 22, 2017
2,893
2,206
SoCal
I had the same issues, my local tesla dealer gave me a gen 1 cable to bring home to try out, it works every time with no issues. the gen 2 cable has issues every time, I have to unplug and re plug it in at the outlet to make it work

I just posted the exact same respond yesterday on another thread with another person having the same problem. I have a MX with Gen 2 and the mobile tech just swapped it out with a Gen 1. Apparently it is very common because he had to do this a lot.
 

BillFres

Member
Feb 26, 2018
15
15
California
Good to see that there are others here, but very disheartened with my call to Tesla Technical Support. I'm 2.5 hours away from a Service Center, and Tech Support told me that other than driving to the Service Center, I should try ordering a new MENA adapter for $35.00 from the website. I've had the car less than a week, and can't charge at home!
 

BillFres

Member
Feb 26, 2018
15
15
California
I had the same issues, my local tesla dealer gave me a gen 1 cable to bring home to try out, it works every time with no issues. the gen 2 cable has issues every time, I have to unplug and re plug it in at the outlet to make it work
Thanks for posting that. I tried it, and my gen2 cable is working. Next time I'm near a Service Center, I'll have to bring the UMC in to be looked at.
 

dcmetro

Member
Jan 9, 2018
184
78
Virginia
I had similar issue (where car would say Cable fault). Went to service center who changed the Gen 2 cable bag. All good now. I would recommend taking it to them. However pls call ahead to ensure they have extras. It took them almost an hour to exchange mine since was very limited and they had to get manager approvals, even for a swap.
 

Kalex

Member
Oct 1, 2017
149
110
New York
Just received a replacement gen 1 UMC cable today, my second. 9 months old MS 75D. Logs showed issue with the cable.

I noticed a few times that the charge rate on the MCU increases to 48amp despite manually setting at 32 amp. This trips the 50amp breaker.
 

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