LG K40 Secret Codes / Dialer Codes – LMX420MM, LMX420AS, LMX420TM

There are 4 variants of LG K40. The Factory Unlocked Version is compatible with GSM as well as CDMA carriers. The rest of the K40 variants are carrier locked and available for MetroPCS, T-Mobile & AT&T.

Most of the dialer codes are common between these variants. Let’s find out the Secret Dialer Codes for all the K40 variants as follows –

LG K40 Secret Dialer Codes – MetroPCS LM-X420MM / T-Mobile LM-X420TM / AT&T LM-X420AS / Factory Unlocked LM-X420QN

There are a total of 7 Dialer Codes for LG K40. We need to use the phone dialer to enter every secret code. As soon as you’ll enter the last digit of the secret code you’ll be directly taken to the Secret Menu.  There is no need to use the call button for dialing the code.

1.  RLZ Debug UI – LG K40 Dialer Code – AT&T LMX420AS / Factory Unlocked LMX420QN

lg k40 at&t secret codes lmx420as


The first dialer code reveals the RLZ Debug UI.  This code works on AT&T & Factory Unlocked K40. It won’t work on MetroPCS & T-Mobile K40.

Open the Phone dialer and dial *#*#759#*#* to get access to RLZ Debug UI.

2. LG K40 IMEI Dialer Code – LM-X420AS/LM-X420MM/LM-X420TM/LM-X420QN

lg k40 imei code

The IMEI code is the universal code for all GSM phones and you must be already familiar with it.

To know your K40 IMEI dial *#06# using the phone dialer.

3. LG K40 Testing Menu Code – lmx420as / lmx420mm / lmx420tm / lmx420qn

lg k40 testing dialer code

To open the “Testing” Menu on LG K40, open the phone dialer and dial *#*#4636#*#*

There are 2 options in the “Testing” Menu. The first one is “Phone Information” and the other is “Usage Statistics” as visible in the above screenshot.

“Phone Info” provides network-related information. We can change the preferred network type as well which is set to “LTE/UMTS auto (PRL)” by default.

secret codes lg k40 testing

“Usage Statistics” keeps a log of time and duration of each app used on the device. It keeps a tab on system apps as well as 3rd party apps.

We can sort apps on the basis of Usage Time, Launch count & App Name as shown above.

4. LG K40 Calendar Info Dialer Code – lmx420as / lmx420tm / lmx420mm/ lmx420qn

LG K40 Secret code for Calendar Info

The next Secret Code reveals the “Calendar Info” on LG K40. The dialer code is *#*#225#*#


5. LG K40 Google Play Services FCM Diagnostics Code – lmx420mm / lmx420as / lmx420tm/ lmx420qn

LG K40 Google Play Services Code

The next K40 secret code shows the Events and Current Status of Google Play Services FCM Diagnostics data.

To get access to this Menu, open your K40 phone dialer and enter this code *#*#426#*#*

6. LG K40 Operator Hidden Menu Code – lmx420mm / lmx420tm

LG K40 Operator hidden Menu

This Hidden Menu code is compatible with the MetroPCS & T-Mobile K40. It won’t work on the AT&T & Factory Unlocked variant of K40.

The dialer code to unlock the Operator Hidden Menu is 277634#*#

There is a huge list of test options as visible in the screenshot above.

7. LG K40 Hidden Menu Code – lmx420mm / lmx420as / lmx420tm / lmx420qn

LG K40 hidden menu lmx420

This is the last and the most useful LG K40 Secret Code. This Hidden Menu code is compatible with all the K40 variants which are AT&T, T-Mobile, Factory Unlocked & MetroPCS.

The Hidden Menu code for K40 is *#546368#*420#

Check out the dedicated post on LG K40 Hidden Menu where we can explore this Menu in great detail.

For any query related to LG K30 & K40, feel free to leave a comment below.


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