Mechanic Wiki: How to Program Mercedes GLS-Class X167 Key Using LAUNCH X431 IMMO Tool

Learn to program a Mercedes GLS-Class X167 key with the LAUNCH X431 IMMO tool. Step-by-step guide, prerequisites, troubleshooting, and expert tips to save on dealer costs.

Quick Answer

Programming a Mercedes-Benz GLS-Class X167 key using the LAUNCH X431 IMMO tool requires the original working key, a compatible new key blank, the X431 device with active IMMO software, and a stable internet connection. The tool connects via the OBD-II port, reads the immobilizer data, and allows you to add or replace keys in about 5–15 minutes. This process saves hundreds of dollars compared to dealer programming.

Introduction to Key Programming for the Mercedes GLS-Class X167

The Mercedes-Benz GLS-Class X167 (2019–present) relies on a sophisticated keyless-go system with an electronic immobilizer that communicates with the engine control unit (ECU). When you buy a blank aftermarket or additional OEM key, it won’t start the vehicle until the immobilizer data is synchronized. That’s where the LAUNCH X431 IMMO tool comes in—it acts as a bridge between the vehicle’s control modules and your new key, writing the necessary encryption codes.

From my years of hands-on work with automotive diagnostic equipment, I’ve seen many DIYers and small shop owners assume that simply cutting a key blade is enough. It’s not. The electronic handshake must match perfectly, or the engine will crank but never fire. This guide walks you through the exact procedure, common mistakes to avoid, and what to do when things don’t go as planned.

Prerequisites and Preparations

Before you start, gather everything you need. Missing one item can waste time or abort the process mid-way.

Required Item	Notes
LAUNCH X431 IMMO Tool	Ensure the IMMO/Immobilizer module is activated in your subscription. Update the software via Wi-Fi before starting.
Original working key	You must have at least one key that currently starts the vehicle. Without it, you’ll need the security PIN and the “Replace All Keys” routine.
New key blank	Must be compatible with the X167 (Mercedes-Benz part number 000-905-73-03 or equivalent aftermarket). Have it cut to match your lock cylinder by a locksmith.
Stable internet connection	The X431 downloads vehicle-specific encryption data on the first programming attempt for that VIN.
OBD-II cable	Included with the X431. Make sure it’s firmly connected to both tool and vehicle.
Battery voltage above 12.4V	Low voltage is the number one cause of interrupted programming. Use a battery charger or jumper pack if needed.
Security PIN (if applicable)	If you have no working keys, you’ll need the PIN – the X431 can often retrieve it from the vehicle with internet access.

Pro tip: Keep the new key away from metal objects and other keys during programming. The keyless-go antenna inside the vehicle is sensitive, and interference can cause a failed write.

Step-by-Step Guide to Programming a GLS-Class X167 Key with LAUNCH X431 IMMO

Accessing the IMMO Function

Power on the LAUNCH X431 device and wait for the main menu to load fully.
Connect the OBD-II cable to the vehicle’s diagnostic port under the dashboard (driver’s side, near the hood release). The tool should detect power and show a connection icon.
Select Diagnostics from the main menu, then choose All Systems or scroll to Immobilizer under the category list.
Tap Mercedes-Benz, then GLS-Class, then X167. Alternatively, use the auto-detect function—this works well if the tool is updated.
The system will communicate with the vehicle. You’ll see the VIN pop up along with the current immobilizer status (e.g., “Key recognized” or “No key programmed”).

Entering Programmer Mode

Insert the original working key into the ignition slot (or bring it inside the vehicle if you have keyless-go). Turn it to position “1” (accessory mode) – do not start the engine. The dashboard lights should come on.
On the X431 screen, navigate to Key Programming and select Add New Key. If you’ve lost all keys, choose Replace All Keys instead—but you’ll need the security PIN.
Follow the on-screen instructions. The tool may prompt you to enter the vehicle’s security PIN. If you don’t have it, the X431 can attempt an online PIN retrieval. This requires a strong internet connection and may take 30–60 seconds.
The device will display a step-by-step procedure, such as “Turn ignition off, remove key, then insert new key within 10 seconds.” Follow each prompt exactly—timing matters.

Programming the New Key

Remove the original key from the ignition. Immediately insert the new blank key and turn it to position “1” (accessory). You should see the dashboard illuminate again.
On the X431, tap Start Programming. Do not touch the key or the device during this phase.
A progress bar will appear. The tool communicates with the ECU to write the new key’s ID into the immobilizer memory. This usually takes 30–60 seconds, but can stretch to 2 minutes on some vehicles.
When the procedure completes, a confirmation message appears: “Key programming successful” or similar. Turn the ignition off and remove the new key.
Test the key immediately: insert it and start the engine. If it doesn’t start, do not panic—some models require a second synchronization step (see troubleshooting below).

Verifying the Programming

Press the lock and unlock buttons on the new key from about 10 feet away. The doors should respond.
Enter the vehicle, keep the key inside, and press the start button. The engine should crank and run.
Check the keyless-go function: with the key in your pocket, touch the door handle to lock/unlock. Then press start with the key still in your pocket.
If any function fails, re-run the programming procedure or try the Remote Control Programming option under the IMMO menu.

Troubleshooting Common Issues

Even with the right steps, things can go wrong. Here are the most frequent problems I’ve encountered and how to fix them.

Problem	Likely Cause	Solution
X431 cannot connect to vehicle	OBD cable loose, vehicle in sleep mode, or incompatible connection	Reconnect the cable firmly. Turn ignition to position “2” (on) before connecting. Try restarting the X431. If still no connection, check the tool’s software update.
“PIN retrieval failed”	Weak internet connection, outdated IMMO software, or VIN not in database	Connect to a stronger Wi-Fi network. Update the X431 through the system settings. If retrieval fails repeatedly, obtain the PIN from a dealership or locksmith (costs $20–50).
Programming aborted halfway	Low battery voltage (below 12.4V)	Charge the battery with an external charger. During programming, turn off headlights, radio, and HVAC to reduce load.
New key works but remote functions don’t	Key blank may be incompatible with remote frequency, or remote not paired	Use a high-quality OEM or certified aftermarket key. Run Remote Control Programming from the IMMO menu. Hold the new key near the steering column during pairing.
Engine starts then dies after programming	Immobilizer not fully synchronized or old key codes still present	Perform the Key Adaptation routine again. If it fails, use Replace All Keys (requires PIN) to clear and re-add all keys.
Tool says “Key already programmed”	The new key may have been used in another vehicle	Some aftermarket keys can be “unlocked” with specialized software. Otherwise, return the key and buy a virgin blank.

Advanced Tips for Experts

Keyless-go range: During programming, the new key must be inside the vehicle’s interior antenna field. Hold it near the center console or the ignition slot. If you have a keyless-go model, do not place the key on metal surfaces.
Lost all keys? Select Replace All Keys in the X431 menu. This erases all existing key codes and lets you add new ones. You must have the security PIN—the X431 can often retrieve it online, but if not, you’ll need to get it from a dealer (requires proof of ownership). Expect a longer procedure, about 15–20 minutes.
After programming, some models require a “learn-in” period: Leave the new key in the ignition in position “1” for 10 minutes without starting the engine. This allows the keyless-go module to fully adapt to the key’s transponder. I’ve seen this solve intermittent starting problems.
Software updates matter: The LAUNCH X431 IMMO module receives updates that add new vehicle models and fix bugs. Check for updates monthly. A failed programming is often caused by outdated software.
Use OEM or reputable aftermarket keys: Cheap blanks from unknown sources may have incorrect transponder chips or poor remote modules. I recommend brands like ADZ, VVDI, or genuine Mercedes parts. For more on compatible keys, check our guide on [link to article on Mercedes key types and compatibility].

Frequently Asked Questions

Q: Can I program a key without a working original key using the LAUNCH X431?
A: Yes, you can use the “Replace All Keys” option, but you will need the vehicle’s security PIN. The X431 can attempt to retrieve it online, but if that fails, you must obtain the PIN from a dealer or locksmith. This procedure erases all existing keys and adds the new ones.

Q: How many keys can I program for the GLS-Class X167?
A: The system supports up to 8 keys. Once you reach the limit, you must delete an old key before adding a new one. The X431 will warn you if you exceed the maximum.

Q: Does the LAUNCH X431 IMMO tool work for older Mercedes GLS models?
A: The X167 generation (2019–present) is fully supported. For the previous X166 generation (2013–2019), you need a different software module. The X431 will detect the correct model if you use auto-detect.

Q: My new key doesn’t start the engine—what could be wrong?
A: First, confirm the key blade is cut correctly (try turning it in the driver’s door lock). Then re-run the programming procedure from scratch. If it still fails, the key blank may be defective or not compatible. Try a different blank from a trusted supplier.

Q: Do I need an internet connection every time I program a key?
A: Only for the first programming of a specific VIN. Once the encryption data is downloaded and stored on your X431, subsequent key additions for the same vehicle can be done offline.

Q: Will programming the key using an aftermarket tool void my Mercedes warranty?
A: Using a diagnostic tool like the LAUNCH X431 does not void the warranty. However, any damage caused by incorrect use—such as corrupting ECU data—is your responsibility. Always follow the manufacturer’s procedures and use the tool as intended.

Conclusion and Next Steps

Programming a Mercedes-Benz GLS-Class X167 key with the LAUNCH X431 IMMO tool is a practical, cost-effective alternative to dealer visits. By following this guide step by step, you can add or replace keys in under 20 minutes, even if you’re new to vehicle diagnostics. Keep your X431 software updated, maintain a healthy battery, and always have a backup working key before you begin.

For more advanced diagnostics and hands-on training with LAUNCH X431 tools, explore our other guides on [link to article on LAUNCH X431 IMMO for other Mercedes models]. And if you ever need professional support, don’t hesitate to reach out—I’ve helped countless technicians and car owners master key programming, and I’m happy to help you too.

About the Author: Erwin Salarda is an Automotive Service Equipment Technician based in the Philippines, specializing in computerized automotive diagnostic equipment such as OBD scanners and wheel alignment systems. Since 2012, he has been actively providing technical support, equipment installation, troubleshooting, after-sales service, and hands-on training for automotive service equipment used by workshops and automotive professionals.

He has received specialized training from international suppliers and manufacturers, including Launch X431 in Shenzhen, China, Lawrence Engineering Company in Guangzhou, China, and 3Excel Wheel Alignment Company in Shenzhen, China. Through these trainings, he developed advanced expertise in automotive diagnostics, calibration, wheel alignment systems, and computerized automotive service technologies.

Erwin Salarda provides professional after-sales support and technical training for automotive diagnostic and wheel alignment equipment, helping clients maximize the performance and proper use of their tools and systems. His experience covers equipment setup, software updates, calibration procedures, troubleshooting, and operational guidance for automotive workshops and service centers.

With more than a decade of experience in the automotive equipment industry, Erwin Salarda continues to support automotive businesses by delivering reliable technical expertise and practical training solutions.

For inquiries and equipment purchases, please visit https://carlifterph.com/