Modem Test Tools in Xiaomi: the hidden capabilities of your smartphone for network diagnostics

Have you ever come across a situation where Xiaomi suddenly loses its network, catches poorly? 4G/5G Or refuse to connect to Wi-Fi, even though other devices are working normally? Most of the time, users run to the service center or try to reset the settings to the factory. MIUI Modem Test Tools (sometimes called Engineer Mode or Service Menu) is not just a secret menu for engineers, but a full-fledged diagnostic tool that allows you to test communication modules without special equipment.

In this article, we will discuss in detail what Modem Test Tools is on Xiaomi, how to get there (including on models from 2023-2026), what parameters can be checked, and most importantly, how to interpret the data obtained to identify problems with the modem, antennas or firmware yourself.

What is Modem Test Tools and Why You Need It in Xiaomi

Modem Test Tools (or Engineer Mode) is a hidden diagnostic menu built into firmware. MIUI It's based on Qualcomm or Mediatek:

• 📶 Testing the strength of the cellular network signal (RSSI, RSRP, SINR) real-time.
• 🌐 Diagnostics of Wi-Fi problems (channel scanning, speed check, interference analysis).
• 📡 Work checks GPS/GLONASS (number of satellites, positioning accuracy).
• 🔄 Analysis of switching between networks (2G/3G/4G/5G, roaming).
• 🔧 Modem settings (manually select frequencies, block operators).

Unlike the standard settings. MIUI, Where only basic indicators (e.g., the number of sticks) are displayed, Modem Test Tools shows the real-world technical parameters of communication that service center engineers use. For example, you may see that the smartphone “sees” the operator’s tower, but can’t connect to it because of the low value. SINR (Signal/Noise ratio is a direct indication of a hardware problem with an antenna or module.

It’s important to understand that this tool doesn’t require root rights (on most Xiaomi models), but some features can be blocked on devices with a closed bootloader (for example, the Redmi Note 12 Pro).+ It is also worth noting that the menu interface may vary depending on the version. MIUI The processor type (Snapdragon vs Dimensity).

How to open Modem Test Tools on Xiaomi: step-by-step instructions

Modem Test Tools are accessed through what is known as Engineer Code, a special combination that you need to enter in the Phone app. However, the login method depends on the model and version. MIUI. Below are the current methods for devices 2020-2026:

Make sure that SIM-card inserted and active

Close all background applications

Use the standard "Phone" application (not third-party dialers)

Connect to Wi-Fi if you plan to test this network-->

Method 1: Using #4636## (for Snapdragon)

This code works on most Xiaomi smartphones with Qualcomm Snapdragon processors (for example, Redmi Note 11 Pro, POCO F5, Xiaomi 13T). Sequence of action:

1. Open the Phone app.
2. Enter the combination: ##4636###.
3. In the menu that appears, select Information (or Phone Information).
4. Scroll down to the Modem Test Tools section.

Method 2: Using #36446337## (for Mediatek)

For devices running Mediatek Dimensity chips (e.g. Redmi Note 12 Pro) 5G, POCO X5 Pro) use:

1. Open the phone and type in ##36446337##.
2. Choose Connectivity → Modem Test.

Method 3: Using the "Service Codes" app (for new ones) MIUI)

Starting with MIUI 14, some codes may be blocked:

1. Download from Google Play app MTK Engineering Mode (for Mediatek) or Qualcomm Engineer Mode.
2. Start it and give access to phone functions.
3. Select Modem Test Tools from the main menu.

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If nothing happens after you enter the code, try adding a # character at the end (e.g. #4636###).

Main sections of Modem Test Tools and their purpose

After you log in, you'll see a menu with a few tabs, and let's look at the most useful ones.

For example, in the Signal Strength section you can see the following parameters:

• RSRP (Reference Signal Received Power - signal power in dBm. Optimal value: from -80 dB -100 dB.
• RSRQ (Reference Signal Received Quality - signal quality. Good value: above -10 dB.
• SINR (Signal-to-Interference-plus-Noise Ratio - signal-to-noise ratio - Normal: above 10 dB.

Diagnostics of problems with the cellular network: a practical case

Let’s say your Xiaomi Redmi Note 13 Pro+ suddenly stopped fishing 5G, This is how you can diagnose a problem with Modem Test Tools:

1. Step 1: Open Network Info and check the current network type. LTE instead NR (5G), proceed to step 2.
2. Step 2. In Band Selection, see which ranges are supported by your operator (for example, for MTS, this is the same as for the band). n78 and n1). If they are marked as Unsupported, the problem may be the modem firmware.
3. Step 3: Return to Signal Strength and compare the values RSRP for 4G and 5G. If 5G worse+ dBm, maybe an antenna 5G damaged.
4. Step 4: Try to manually select a range 5G Band Selection and restart your smartphone.

If, after these manipulations, 5G not appearing, the reasons may be as follows:

• 📱 The modem firmware is outdated (you need to update via Fastboot).
• 🔌 SIM-card does not support 5G (check with the operator).
• 📡 Operator shut down. 5G in your area (check on the provider’s website).

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If you see Out of Service status in Network Info, but SIM-The card works on another phone – it is 90% probability of hardware malfunction of the modem.

Wi-Fi Testing: How to Find the Cause of Slow Internet

If your Xiaomi is not working well with Wi-Fi (low speed, connection breaks), Modem Test Tools will help identify the cause.

• 📊 Channel Width is channel width. Optimal: 80 MHz for 5 GHz or 40 MHz for 2.4 GHz.
• 📶 RSSI — All right, above. -60 dB.
• 🔄 Link Speed – current connection speed (must match the router tariff).
• 🛑 Retransmit Rate: Percentage of packet retransmissions, above 10%, a sign of interference.

Typical problems and solutions:

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If you see a high Retransmit Rate in the Wi-Fi Test (more than the above). 20%), Try changing the channel to 5 GHz with DFS (for example, 52–64) off-the-shelf-DFS (149–165).

Risks and limitations of Modem Test Tools

Despite its usefulness, Modem Test Tools can be dangerous if used incorrectly.

⚠️ Note: Changing the settings in the Band Selection section (for example, disabling all bands) can lead to complete loss of the network.

• ❌ Don't change. IMEI It's illegal and it's blocking the network.
• ❌ Do not turn off ranges unless you are sure of their purpose.
• ❌ Do not update the modem firmware through unofficial sources.

Also consider the limitations:

• On some models (for example, Xiaomi 14 Ultra) some of the features are blocked.
• The menu data is updated with a delay (up to 5 seconds).
• Not all options are decrypted – some are for Xiaomi engineers only.

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If after the changes in Modem Test Tools smartphone stopped seeing the network, reset the modem settings using the code # # #72786## (does not work on all models).

Modem Test Tools for Xiaomi

If for some reason you can’t open Modem Test Tools (for example, the code doesn’t work on your model), use alternative diagnostic methods:

• 📱 NetMonster app – shows detailed information about the cellular network (including neighboring towers).
• 🌐 WiFi Analyzer – scans Wi-Fi networks and shows the load of channels.
• 📡 GPS Status & Toolbox – Testing Satellite Navigation.
• 🔧 ADB-commands for advanced users (e.g. adb shell service call telephony 19) i32 1 for net reset).

To check the speed of the Internet, we recommend:

• Speedtest by Ookla – Speed Testing 4G/5G.
• WiFi SweetSpots – to analyze indoor Wi-Fi coverage.

FAQ: Frequent Questions About Modem Test Tools on Xiaomi