Powertrain Problem ID: 963

From my list: 963 with rank 4 = internal PEM fault. Remedy says replace PEM. Not good news but the service center would know for sure. I would say don't drive if you can't charge.

PV-EV said:

From my list: 963 with rank 4 = internal PEM fault. Remedy says replace PEM. Not good news but the service center would know for sure. I would say don't drive if you can't charge.

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I got that error (DMC FW: Line Current Not Equal Request fault) when one of the fuses blew to the battery heater. It would retry every couple of minutes just like yours did with repeated thunks from the charger. But I'm not sure that's your problem if it happened at the end of a 40A charge. By then your battery would have been warm enough so as not to need pack heating.

@hcsharp
Is there a thread where a list of errors and debug errors is posted???

I was getting a similar "powertrain..." error and Bethesda service replaced one of my PEM fans. The problem has been gone for about a month now.

Botbldr45 said:

@hcsharp
Is there a thread where a list of errors and debug errors is posted???

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I use Open-Vehicle-Monitoring-System/ovms_server_tr.vece at master · openvehicles/Open-Vehicle-Monitoring-System · GitHub

Thank You for the reference:biggrin:

tvuolo said:

I got my roadster back yesterday... Seems like 2 fuses blew.

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I'll repeat an old story and apologize if it is a repeat for some of you. When we attended the inauguration of the Roadster charger at Harris Ranch in 2010 (long before the Superchargers), we left our car charging during the night in preparation for the trip home. In the morning we discovered a fault, with a "Service Required" warning on the VDS. Fortunately, JB Straubel was speaking at the event and had driven there in a Roadster. When we called him over to show him the problem, his response was, "Why do I come to these events?" Nevertheless, he diagnosed the problem with help by phone from HQ and determined that the line input fuses had probably blown due to a drop in the line voltage causing the current draw to increase as the controller was trying to maintain the power level. So, we opened the PEM and JB swapped the fuses with the ones from his car that was already charged. His was a 2.0 and ours 1.5, so the replacement fuse value was larger, but that was OK. We took the car in after we got home for the original fuse replacements to be installed. A subsequent firmware update a month or so later was supposed to improve the timing of the control circuit so this failure would not happen with a similar voltage drop.

Love that photo. A moment in Tesla history!

For starters I wouldn't try to run your waffle iron inside the car...

I'm glad it wasn't a catastrophic PEM failure! Not a cheap fix but I'm sure could have been much worse.

tvuolo said:

I hadn't heard that story. Thanks for sharing!

Is there anything I can do to prevent the fuses from blowing again?

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Well, unless your firmware is way out of date, then it seems that the change made in 2010 may not be sufficient for all cases. Since you were charging at 40A there should have been more headroom for current to bump up than when my car was charging at 70A at Harris Ranch. That means the failure on your car is a bit disconcerting. I wonder whether there was some glitch in the PEM causing the current draw to surge. Cosmic rays, anyone?

Do you have any idea whether there were any power anomalies at the time the failure occurred?

Thanks for this tread, guys. I know it's 2 years later, but I just had the same problem. Very cold out 17 degrees F, and the car needed to heat the battery. That's when it failed. I'll be interested to see if it's the fuses.

Easy to check the charging fuses with an ohmmeter. Pop the small lid on the top of the PEM and they are right there.

PV-EV said:

Easy to check the charging fuses with an ohmmeter. Pop the small lid on the top of the PEM and they are right there.

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I've only had the Roadster since July. If you had any photos you could post of exactly where I should be looking to find the fuses and what these particular fuses look like, I would appreciate it. I do have an ohmmeter, just no experience with the guts of my roadster.

Since PV-EV said to pop the lid on the PEM I assume he means these:

Right compartment but not the fuses I meant. Those are for the blowers. Wouldn’t hurt to check them too but I think they throw a different error if blown. The main charging fuses are at the bottom of the compartment, below the big cables. You can see them on the diagram in the photo. Forgot they were so buried. For a good description of getting in there look at the posts about annual PEM cleaning. You are going to want to know how to do that anyhow...Happy New Year, and good luck.

PV-EV said:

Right compartment but not the fuses I meant. Those are for the blowers. Wouldn’t hurt to check them too but I think they throw a different error if blown. The main charging fuses are at the bottom of the compartment, below the big cables. You can see them on the diagram in the photo. Forgot they were so buried. For a good description of getting in there look at the posts about annual PEM cleaning. You are going to want to know how to do that anyhow...Happy New Year, and good luck.

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Just want to reiterate be sure to shut down the APS (high-voltage system) before opening the access cover. It's supposed to do it automatically but don't bet on it because your life is at stake.

To add to what PV-EV said, there is a third set of fuses in that photo down and to the left of the red circled ones. You open them with a flat blade screw driver. They are for the coolant heater. My heater went bad under warranty and started periodically blowing those fuses. I can't remember for sure but it might have thrown the same error message every time one of those fuses blew.

Botbldr45 said:

Is there a thread where a list of errors and debug errors is posted???

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The TMC Wiki has a list of the errors with suggestions from users. I just updated the list to include some missing errors and the fix for tvuolo's Roadster.