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PCS_a054 – Charging stopped due to large voltage drop

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About two weeks ago I woke up to find the notification on my Tesla Model 3 – PCS_a054 which took me to the following information:

PCS_a054 – Charging stopped due to large voltage drop Remove extension cords / Have wiring inspected

Charging has been interrupted because the onboard charger in your vehicle has detected an unusually large voltage drop.

Likely causes of this issue include:
– Problems with the building wiring and/or the wall outlet
– An extension cord or other wiring that cannot support the requested charge current

This issue can also result from turning on electric devices that draw a lot of power from the same branch circuit while the vehicle is charging.

If this issue has occurred multiple times at your normal charging location, contact an electrician to inspect the electrical installation.  They should check the following
– Any installed charging equipment and its connection to the building wiring
– The building wiring, including any wall outlet used with a Mobile Connector
– The electrical connection to the power utility line where it enters the building

Discuss with the electrician whether the charge current on the vehicle should be lowered, or if the installation should be upgraded to support a higher charge current.

As this alert is usually specific to external charging equipment and power sources, and it does not typically indicate an issue with your vehicle that can be resolved by scheduling service, it is recommended that you:
– Try charging with multiple, different types of charging equipment at different locations
– Contact an electrician to inspect the wiring and equipment at your normal charging location

You can also try charging your vehicle using a Tesla Supercharger or Destination Charging location, all of which can be located through the map on your vehicle’s touchscreen display.  See Maps and Navigation for more details.  Additional third-party charging stations may also be available in your area to help you to pinpoint the issue.

For more information on troubleshooting Mobile Connector or Wall Connector status lights, refer to the product’s  Owner’s Manual at Charging & Adapter Product Guides.  If using other external charging equipment, refer to the manufacturer’s provided documentation for troubleshooting tips.

Looking through my notifications, I noticed I received three notifications at 2:04am.  The first notification was

BMS_a0174 Unable to charge – Disconnect and retry

followed by

PCS_a053 Charge rate reduced – Unexpected voltage drop – Remove extension cords / Have wiring inspected

and last was the what I detailed above

PCS_a054 Charging stopped due to large voltage drop – Remove extension cords / Have wiring inspected


I had previously written about a charging error I was getting, which seemed to be resolved when I switched Mobile Connectors – fortunately I had a second one because my wife also drives a Tesla.  I did re-use the same plug that goes into the NEMA 14-50 outlet, as my Model 3 only came with the standard wall outlet plug.  As best I can tell, the Mobile Connector units are the same.  I had brought in the Mobile Connector giving the errors to the Tesla service center, and they informed us that it was a firmware issue that would be resolved with the next firmware update.  I’m not aware of any way that I can check the firmware on the Mobile Connector.  I thought that the firmware gets updated when the device is plugged into the car – essentially downloading the firmware through the connection to the car. At today’s mobile service appointment, the Tesla technician said the Mobile Connector actually gets updates through wifi, as long as it is kept plugged into the wall.  That is different from what I read, so I’ll try to look that up and see what the most accurate answer is to that.  I also wish there were a way that I could see what firmware version the Mobile Connector currently has installed.

When I switched Mobile Connectors, the error I previously received went away.  Either the problem was with the original Mobile Connector (firmware or hardware), or possibly it was the plug hadn’t been properly seated into the Mobile Connector.  I’d read that some people solved this original issue by just removed the plug adapter from the Mobile Connector and re-attaching it.  This would make sure that it was fully seated into its spot.  At some point I will try using the original mobile connector and update the threads.

Back to the voltage drop issue.  I was concerned maybe it was a problem with my home wiring or the outlet failing.  I contacted Tesla service and they arranged a mobile service appointment that I had today.  The technician replaced the NEMA 14-50 plug component, saying that it is possible the original one was failing – it is 3.5 years old at this point.  The invoice says he replaced part 14-50 Gen II Smart Adapter (1099344-10-D).  It is currently on Amazon for $79.99 or $45 directly through Tesla.   I’m not sure why they marked up the price so much through Amazon.  For me, it was covered under the warranty.

As I have been using the old plug for the past two weeks without any additional errors, I’m not 100% convinced that there was a problem with the plug adapter.  I also don’t think there is a problem with my electrical wiring or outlet, but that remains a possibility.  I would have thought if that was indeed faulty, I would continue to get errors regardless of which Mobile Connector or plug adapter I’m using.

I’ll update if I get any additional new errors.

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