Alientech KESS3 Unlock Module — Bosch MDG1 Unlock Kit

Alientech KESS3 Unlock Module — Bosch MDG1 Unlock Kit

The KESS3 Unlock Module is the connection kit Alientech released for opening locked Bosch MDG1 control units in the workshop. It is not a tool on its own but an accessory that works with KESS3: it unlocks the unit in boot mode, and once the lock is off, KESS3 takes over access to the memories. It arrived with Alientech's 3.50 update of 3 September 2026.

The problem: "locked" MDG1 units

Bosch's MDG1 family has been leaving the factory locked since 2021. The lock closes access at the boot stage: even with the boot connection correctly made, the microprocessor does not enter protected mode and the memory cannot be read. The cable is right, the soldering is right, the connection is right — and the unit still does not open the door.

In the workshop that meant one of two things when a locked MDG1 arrived: turn the job away, or send the unit to someone who could open it. Both cost time, and one of them costs the customer. The Unlock Module brings that step back inside the workshop.

What the kit does

The kit makes the physical connection to the unit's boot line and provides the hardware the Unlock procedure needs. Three steps:

1. Connection. The unit goes on the bench and is connected to the boot line with the 26-way ribbon cable and the adapter board. On some units the connection runs through the VFL3 signal, on others through the adapter board — cables for both are in the box.
2. Unlock. KESS3 runs the unlock procedure through the Unlock Module. This is the step that gets the unit into protected boot mode.
3. Programming. With the lock off, the unit behaves like any other boot unit: memories are read, written and backed up in full.

Supported locked MDG1 units

The MD1 units are mostly diesel applications, the MG1 units petrol. The list covers passenger cars, light commercials and high-performance SUVs alike.

Which vehicles? (2021 onwards)

This is the coverage published with release 3.50, and it grows with updates. If the unit in front of you is not on the list, send us the unit number and we will check it with you.

What is in the box

What you need for it to work

• A KESS3 tool — the Unlock Module does not work on its own.
• CAR BENCH/BOOT activation — unlocking and boot programming sit in that scope.
• An active subscription — new protocols only reach tools whose subscription is running.
• The unit on the bench — this is not an OBD job; it needs a boot connection.

Who it is for

• Chip tuning workshops working with KESS3
• ECU repair services handling post-2021 vehicles
• Workshops turning jobs away because of locked units
• Electronics services that back up and replace units

Frequently asked questions

Does the Unlock Module work on its own?

No. It is an accessory that works with KESS3; KESS3 runs the unlock procedure and the kit provides the connection and the hardware it needs.

What becomes possible after the unlock?

The unit can be read, written and fully backed up in boot mode. Everything after the unlock is the familiar KESS3 boot flow.

Can this be done over OBD?

No. Unlocking needs a boot connection, which means taking the unit out of the vehicle and onto the bench.

Which subscription is required?

CAR BENCH/BOOT activation on the KESS3 side, plus an active subscription. A tool with a lapsed subscription cannot download the new protocols.

What if my unit is not on the list?

Coverage grows with updates. Send us the unit number and we will check whether it is covered and which method opens it.

How does this differ from Korhex?

Both give access to protected units, but they belong to different tools: Korhex works with Flex, this module with KESS3. Whichever tool you work with, that side's solution is the one for you.

Is soldering required?

It depends on the unit: some are handled with the adapter board, others need a soldered connection. That is why spare soldering wire is in the box.