LG K30 & K40 charging problems -not charging/port replacement

LG K30/K40 uses a Micro-USB 2.0 charging port without Quick Charge support. By spending a little more on LG Stylo 6, you get the fast charging support. A fast charger takes around half an hour to charge the battery from 0-50%.

LG K40 Fast Charging

With the original LG charger, K40 can be charged from 0-100 in less than 2 hrs.  This is a decent charging speed.

You can face 2 kinds of charging problems on LG K40 – Slow Charging or No charging. There can be multiple reasons for this behavior. Let’s try to evaluate & fix the charging issues on LG K30/K40 –

LG K30 & K40 Charging Problems


a. Slow Charging

lg k40 slow charging

Using a cheap charger can do more harm than good. Apart from slow charging, it can also damage the charging port.

Make sure you’re using the original charger supplied with your K40.  Stay away from cheap unbranded chargers.

You can buy the original LG K30/K40 charger from the below link –

LG K30/K40 Original Micro USB charging cable & Adapter

LG K30/K40 Charger Specs
LG K30/K40 Original Charger Specs

If using a 3rd party charger, make sure the specs are the same as the original charger.

LG K30/K40 uses a 1.8A charger. Using a charger with a lower current rating will take more time to charge the battery.



b. Not Charging

 1. Software Glitch

lg k40 not charging

If your phone turns on but it fails to charge, it may be due to a software glitch. Before drawing conclusions, we should soft reset the phone and try to charge it again.

Long-Press the power button and tap “Power off and restart” to reboot the phone.



lg k40 force restart

If your K40 screen is frozen, it may be charging but you cannot notice it due to the frozen charging icon. In such a case, we need to force restart the phone using the volume down and power button.

Press and hold, Volume Down + Power key for 5 seconds or until the phone restarts.


If it still fails to charge, move on to the next troubleshooting step –

2. Charging Mode Disabled

lg k40 charging port test

On LG K30/K40 Hidden Menu, there’s an option to toggle on/off charging.

We can use this option to test the Charging port.

Open your K30/K40 phone dialer and dial 277634#*#

This brings us to the Operator Hidden Menu page.

Scroll down to the bottom and select the last option i.e. “Charging Mode On/Off”.

lg k40 won't charge

In the first screenshot, the charging mode is enabled and I’ve connected the phone to my computer using a Micro USB Cable. The phone is charging, as indicated by the charging icon.

In the second screenshot, the charging cable is connected but the charging mode is disabled. So, even though the phone is connected to a charger it’s not charging. The charging mode value has changed to “Charging_enabled : 0”

We can use this test to troubleshoot charging issues on K30/K40.


3. Bad Charger

lg k40 charging problems

The next thing we need to look for is the proper functioning of the charger adapter/micro USB cable.

Check if there is a loose connection between the charging cable pin and the charging port. Try different positions to establish a proper connection. Also, try to replace it with another micro USB charger.

lg k40 charging cable

Connect your phone to the computer via a USB data cable. Has the phone started charging? Is it detected by the computer?





 4. Bad Wall Outlet

lg k40 charging port

The next thing you need to check for is the wall charging socket. Switch to another socket and try to charge your phone once again.


6. Battery Issues

lg k40 battery question mark

Do you see a “battery with a question mark” on the screen when connected to a charger? Either the Micro USB cable or the battery is faulty.

First of all, use a different cable to charge the phone.

If this doesn’t fix the issue, the battery may be damaged.  Water or physical damage can corrode/break the battery terminal connection.


lg k40 battery model number bl-t39

You should get yourself a replacement LG K30/K40 battery.  The LG K40 battery model number is BL-T39. You can get it for around $10 on eBay.


lg k30 battery model number bl-t36

The LG K30 battery model number is BL-T36 as shown above. The OEM LG K30 battery sells for around $13.5 on eBay.


7. LCD Problem/Black Screen

lg k40 screen replacement

If your K40 LCD has gone bad, the phone will turn on with a black screen.


lg k40 notification led


Try to turn on the phone and make note of any vibration, sound, notification light, screen flickering, etc. If the phone turns on with a black screen, you need to get a replacement screen to fix the issue.

lg k30 screen replacement kit cost

You can get a replacement LCD with a frame for your K30 for around $34 at Amazon.

LG K40 screen replacement kit cost

LG K40 LCD with Frame comes for around $32 at Amazon.

5. Defective Charging Port

lg k40 charging port

In the majority of the cases, the real culprit is the charging port. A bad charger or water damage can break it.

The charging port is connected to the motherboard.

Send your phone for repair if it’s under the warranty period.

To do it yourself, buy a replacement charging port and follow the below video to fix it –

lg k30 replacement charging port

The LG K30 replacement charging connector comes for around $7 at amazon. This is a pack of 2 charging connectors.

LG K40 replcement charging port

Likewise, the cost of 2 charging connectors for K40 is around $7.5 at Amazon.


Follow the below video to replace the LG K40 charging port on your own –

8. Firmware Update Stuck

lg k40 firmware update stuck

If your K30/K40 is “stuck on firmware update”, the charging icon won’t show up on the screen.

To get back to the normal mode, follow the below guide –

LG K30 Firmware Update Stuck 

LG K40 Firmware Update Stuck

9. Dead/Bricked

lg k40 dead / bricked

If all the above troubleshooting steps fail to fix your LG K30/K40 charging problems, your phone must be dead.

Only a replacement motherboard can fix your phone now.



Were you able to fix the charging issue on your K30/K40? Please share your experience in the comment section below.




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