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Charging error codes - CP_a046 - CP_a139 - UMC_a012 - UMC_a017

Mar 14, 2021
11
6
Dallas
I tried to search for these error codes but nothing came up. I have a 2020 M3 with around 6K miles. I live in Texas and in the last couple of weeks my UMC (mobile charger gen 2) has lowered the amperage to 16A due to heat errors. I didn't think much about initially because I had started the charge in my garage around 9pm whereas my garage is probably 95f and the plug is hot from an outside wall. I charged a few days later at midnight with no errors.

Then, this morning I came out again with more notifications. These notifications started immediately upon charge with these codes in order:

12:00 am CP_a046 - Charging equipment communication lost
12:00 am CP_a139 - Check equipment for error code or message
12:00 am UMC_a012 - Charging equipment communication error
12:47 am UMC_a017 - Charge rate reduced - Wall plug temperature high - Wallout let and wiring inspection recomended

I have an appt with Mobile Tesla about swapping my charger but is this something that happens regularly? Could it be the wall outlet? Could it be the car? I have found that my neighbor next door who also has a M3 ran into the same issue and decided to lower from 30A to 28A in the car. He thinks its too hot in the garage but I think this honestly defeats the purpose and we need to get to the root cause.

Thanks,
 

Darmie

Super Member
Supporting Member
Jan 13, 2016
2,055
1,360
Clear Lake TX.
No expert by any means however, most issues that I have read about with a HPWC comes down to a re tightening of the feed lugs. As recommended, have an electrician verify.
I have two Gen 2's one on the outside and one on the inside of the garage. I've been using the one on the inside for several years now with no heat issues being on the inside of the garage.
I will say my charging cable does get very warm at max amperage so I usually keep mine down to 48amps on most charging events.
 
Mar 14, 2021
11
6
Dallas
Electrician stopped by and checked everything. He stands behind everything as installed. All areas were tight etc. I did notice that Leviton is the plug and I’m sure Tesla will complain about that. Why didn’t you opt for Hubbell or the Bryant? Electrician said the Leviton was UL approved but wouldn’t mind coming back if I asked him to install a $21 Bryant. 😜
 
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Darmie

Super Member
Supporting Member
Jan 13, 2016
2,055
1,360
Clear Lake TX.
So sorry I miss read your post. You're using a mobile charger that came with the car and I take it that you are using a NEMA 14:50 receptacle? It is possible if you are removing and reinstalling your UMC, this will create wear on the receptacle. This will cause an over heating issue. If the electrician stopped by and did not note any issue then it could very well be the charger unit.
 
Mar 14, 2021
11
6
Dallas
So sorry I miss read your post. You're using a mobile charger that came with the car and I take it that you are using a NEMA 14:50 receptacle? It is possible if you are removing and reinstalling your UMC, this will create wear on the receptacle. This will cause an over heating issue. If the electrician stopped by and did not note any issue then it could very well be the charger unit.
The mobile gen 2 charger 14-50 has only been removed 1 time from the plug since I bought the car. The communication messages appeared again when I did a test charge just now. I think it’s the cable charger or maybe the 14-50. Will report back what Tesla says.
 
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Mar 14, 2021
11
6
Dallas
The mobile gen 2 charger 14-50 has only been removed 1 time from the plug since I bought the car. The communication messages appeared again when I did a test charge just now. I think it’s the cable charger or maybe the 14-50. Will report back what Tesla says.
I think my last note was unclear. I think it’s the UMC gen 2 mobile connector or maybe my 14-50 Tesla $35 plug.
 
Mar 14, 2021
11
6
Dallas
I traded UMC with my neighbor overnight and still tried to charge at 32A. About the same warning messages and notes appeared in Tesla/Services/Notifications overnight as before. Now I'm starting to think the UMC cabling is just too thin... or maybe something is up with my car. My neighbor again has just gotten used to lowering the amperage to around 28A and he says it goes away. Would be interested if other people in Texas check the messages overnight after a charge. :)
 

Amped412

Member
Mar 2, 2021
137
118
St. Louis, MO
I traded UMC with my neighbor overnight and still tried to charge at 32A. About the same warning messages and notes appeared in Tesla/Services/Notifications overnight as before. Now I'm starting to think the UMC cabling is just too thin... or maybe something is up with my car. My neighbor again has just gotten used to lowering the amperage to around 28A and he says it goes away. Would be interested if other people in Texas check the messages overnight after a charge. :)
I'm not in Texas but I have the same set up as you. I use a Gen 2 UMC charge cable with a 14-50 adapter. I haven't had one error message and can sustain 32A easily. It's very odd you tried a different UMC and it still had the error messages pop up.
 
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Mar 14, 2021
11
6
Dallas
I'm not in Texas but I have the same set up as you. I use a Gen 2 UMC charge cable with a 14-50 adapter. I haven't had one error message and can sustain 32A easily. It's very odd you tried a different UMC and it still had the error messages pop up.
My mobile Tesla appointment asked to be delayed from Tuesday of next week for another week and requesting additional pictures and will pull diagnostic information.
 
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agreif

Member
Mar 3, 2020
42
12
Chicago, IL
Where do you get the charging error codes? I've gotten the notification that charging has stopped before, but when I select the notification and it goes into the app, it just goes to the main screen, not any error or similar screen.
 
Mar 14, 2021
11
6
Dallas
Where do you get the charging error codes? I've gotten the notification that charging has stopped before, but when I select the notification and it goes into the app, it just goes to the main screen, not any error or similar screen.
You can only get the notifications from the car itself so the path it something like this: Tesla Display/Services/Notifications (They disappear after about 24 hours) There are notifications every day by the way when something is up...
 

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