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Charging problem after PEM reconnected wrongly @ annual service

NigelM

Recovering Member
Apr 3, 2011
13,386
555
Northern Virginia
Roadster still running beautifully after 8 years went in for annual service last week. Took her home after a few days (why did it take 3 days?) and on plugging in I she wouldn't charge just giving me a message to "Connect Charge Cable". Back to Tesla the next morning as range was getting low.

4 days later Tesla writes to me “..the power cable in the PEM was shorted to ground during re-installation of PEM on the last service visit". We loosened the power cable and rotated connection. We retorqued everything and tested the charging cable and the vehicle now is charging properly.” Range was low so they charged the car overnight (I guess now they used my 110v cable seeing as how it was tossed in the trunk), my wife picked up the car today and took her home. However, Roadster still won't charge properly as we now get the error code 935 "Line Voltage Lost Sync" which is normally an indicator of bad power or a tripped breaker; sooo, have now tried 4 different chargers with the same result each time. Roadster will trickle charge on the original 110v cable (despite the 935 message) but that's all.

Clearly it's not a charger issue and car will go back to Tesla for the 3rd time tomorrow. BTW, Tesla service wants to check my charger cable just in case o_O ....I asked them which one, the Tesla HPWC, the Gen 2 Tesla Mobile Connector, my Clipper Creek HCS-60 or the Roadster 110v yellow cable?

/rant

Any thoughts/comments on the likely after-effects from that main power short on the PEM would be welcome.

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Last edited:

hcsharp

Active Member
Jun 7, 2011
3,385
1,345
Vermont
If the black wire going into the PEM from the charge port is still grounded or the large fuse on that wire is blown it could result in the symptoms you are experiencing. When charging on 120v (yellow cable) the black wire is grounded at the breaker panel so you may not notice any problem until you connect to 240v. When you send the car back don't put the yellow cable in the trunk. Only give them your CAN SR so they are forced to test it on 240 or 207v.

BTW I'm happy to hear that you're still enjoying your Roadster after 8+ years! We both got ours about the same time and mine has been a mostly reliable daily driver for going on 9 years.
 

X.l.r.8

Supporting Member
Feb 18, 2018
1,457
915
Toronto/Miami
When I was having separate issues charging I was hoping for a blown fuse in the PEM so I could swap one around to at least accept a charge on 120v. I would point to the PEM fuses also. One is probably blown
 

thefortunes

Active Member
Jun 14, 2013
1,078
1,268
Wisconsin
+1 to responses above.

One of the times I put the PEM back in I mistakenly did EXACTLY what they describe and one of the high voltage cables was grounded. Loosened, rotated, retightened and all was good.

My mistake didn't blow a fuse, but that certainly could have been the result.

I would open the access panel on the PEM and look to see if another HV cable is still grounded.
 
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NigelM

Recovering Member
Apr 3, 2011
13,386
555
Northern Virginia
If the black wire going into the PEM from the charge port is still grounded or the large fuse on that wire is blown it could result in the symptoms you are experiencing. When charging on 120v (yellow cable) the black wire is grounded at the breaker panel so you may not notice any problem until you connect to 240v. When you send the car back don't put the yellow cable in the trunk. Only give them your CAN SR so they are forced to test it on 240 or 207v.

This makes a lot of sense. Thanks Henry @hcsharp

Tesla called in a "Senior Area Roadster Technician" today; I communicated in writing via email and text and then my wife took the car over and put the service guys on the phone so I could walk them through the issues and the suggestion on what to look for. For the moment, I'm loath to start opening up the PEM myself as I don't want to give anyone the excuse that I have messed around with it.

(Aside: why can't the service folks have access to phones anymore?? It's ridiculous that they had to use my wife's phone to call me)
 

hcsharp

Active Member
Jun 7, 2011
3,385
1,345
Vermont
(Aside: why can't the service folks have access to phones anymore?? It's ridiculous that they had to use my wife's phone to call me)
It's Tesla's new policy and it's making a lot of people angry. Hopefully they will see the light and figure out it's doing more harm than good.
 
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NigelM

Recovering Member
Apr 3, 2011
13,386
555
Northern Virginia
Update:

Tesla called(!), wanted to blame non-charging on the CAN Sr; when I explained how it worked and why that couldn't be they then suggested to come to my house and check on my HPWC. I said sure but then they should also check my Clipper Creek HCS, and my Tesla UMC, and my Tesla 110v cable, after all I had the same result from all the different charging options with/without the CAN. [pause] "We're going to keep looking at it in the service center....."
 
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X.l.r.8

Supporting Member
Feb 18, 2018
1,457
915
Toronto/Miami
What are they using there then? They should have a charger there. Mine sees probably 3 roadsters and they have 2. In fact they used both on my car to make sure they were working after blowing the dust off them. I hope they don’t start charging you to fix their mistakes.
 

NigelM

Recovering Member
Apr 3, 2011
13,386
555
Northern Virginia
What are they using there then? They should have a charger there. Mine sees probably 3 roadsters and they have 2. In fact they used both on my car to make sure they were working after blowing the dust off them. I hope they don’t start charging you to fix their mistakes.

It wasn’t very clear to me what they tried the other day (I suspect it was my 110v cable). Previously there were 7 service reps, now there are 2 who look pretty overloaded and detailed Is harder to come by when most communication is automated text messages telling you to check the app.

Tesla have been good about fessing up to their error and seem to be taking full responsibility (so far).
 
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hcsharp

Active Member
Jun 7, 2011
3,385
1,345
Vermont
What are they using there then? They should have a charger there. Mine sees probably 3 roadsters and they have 2. In fact they used both on my car to make sure they were working after blowing the dust off them. I hope they don’t start charging you to fix their mistakes.
That's what bothers me the most. The fact that they don't even have a method of charging a car that's only 8 years old. Maybe I'm biased because I sell adapters but most service centers (like X.l.r.8's) have at least shown enough respect to acquire a Roadster charger or an adapter of some sort. Not doing that is incompetent and disrespectful IMHO. There's a lot of Roadsters in Northern VA. It's not like they only see 1 or 2 each year.
 

gregd

Active Member
Dec 31, 2014
2,538
1,769
CM98
That's what bothers me the most. The fact that they don't even have a method of charging a car that's only 8 years old. Maybe I'm biased because I sell adapters but most service centers (like X.l.r.8's) have at least shown enough respect to acquire a Roadster charger or an adapter of some sort. Not doing that is incompetent and disrespectful IMHO. There's a lot of Roadsters in Northern VA. It's not like they only see 1 or 2 each year.
My SC finally got "permission" to get a CAN-SR so that they can charge Roadsters, after several years of saying they couldn't do that. Works perfectly.
 
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NigelM

Recovering Member
Apr 3, 2011
13,386
555
Northern Virginia
Just closing this one off....

Tesla actually went over and above to get things right again: They didn't find any further issues but disassembly and reassembly of PEM connections etc has fixed the charging issue; everything points back to the PEM connections post-service. However, Tesla delivered the car back to my house with 2 Technicians who checked over my HPWC, Clipper Creek, UMC etc. Looks like the problem had blown my Tesla Gen 2 UMC so they are going to replace that.

Incidentally, new FW on the Gen 2 UMC (connected via Can SR) does cause Error #1086 to pop-up but it then disappears and Roadster will charge normally.
 

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