INSTALLATION
2-STEP MANUAL
4 min

SCR AdBlue / DEF Delete & PACKAGE DEAL | 2-step

This guide provides a complete two-step installation walkthrough for 2014–2019 Mercedes-Benz C and GLC classes. It covers vehicle preparation, selecting the AdBlue Block Reset and Delete scripts with the control knob, “Remaining Starts” troubleshooting, LOGFILE instructions, and removal of the SCR fuse in the trunk under the floor.

Published by
OBDtune Team
Updated
Dec 18, 2025

Table of Contents

SCR AdBlue / DEF Delete & PACKAGE DEAL

This guide explains how to use the OBD module on the 2014–2019 Mercedes-Benz C- GLC- classes with 2.1L OM651 and 3.0L OM642 engines.

Depending on your order, this instruction applies to:

  • SCR AdBlue / DEF Delete
  • PACKAGE DEAL

Before Starting

  1. Before using the OBD module, please read the full instructions from start to finish.
  2. Make sure the vehicle battery is fully charged.

    If possible, start the engine and let it run for about 30 minutes before installation. This helps recharge and stabilize the battery.

    Do not begin the software installation with a weak battery. A weak battery may interrupt the installation process and cause errors.

    You can connect a battery charger to recharge the battery, but make sure to disconnect it before starting the software installation.

  3. Disconnect all aftermarket devices connected to the CAN bus, such as diagnostic tools, trackers, tuning modules, alarm systems, or other third-party electronic devices.

DEF / AdBlue Level

Before starting the installation, fill the DEF / AdBlue tank to 100%.

If the tank is around 70–90%, top it off to full.

Do not overfill the tank to the neck. Overfilling may cause the ultrasonic level sensor to read incorrectly.

Package Contents

Your package includes:

  • OBD module
  • microSD card already installed in the OBD module

All required installation files are already loaded on the microSD card.

During the installation process, you will see the available scripts on the screen:

  • Step 1: AdBlue Block Reset
  • Step 2: NoSCR

    or Stage1 + SemiDelete

    or Stage1 + FullDelete

  • Factory firmware

Use only the script required for your installation step.

The Factory firmware should only be used if we instruct you to restart the installation from the beginning. Do not use the Factory firmware unless we specifically advise you to do so.

How to Turn the Ignition ON

Turn the ignition ON, but do not start the engine.

To turn the ignition ON:

  • 1. Insert the key into the ignition.
  • 2. Turn the key to the second position.
  • 3. The dashboard warning lights should turn on.

Do not start the engine during the OBD module procedure.

Important Notes

  • Make sure the battery is fully charged.
  • Do not remove the OBD module while the LED is blinking normally.
  • Do not switch the ignition OFF during the procedure.
  • Make sure the microSD card is fully inserted into the module before starting.
  • Make sure the correct microSD card is used for each step.
  • Disconnect all aftermarket devices connected to the CAN bus before starting the installation.
  • Do not install the Factory software before an emissions test or a dealer visit unless we specifically advise you to do so.

Installation Steps

This procedure includes two required software steps:

  • 1. Step 1: AdBlue Block Reset
  • 2. Step 2: NoSCR

    or Stage1 + SemiDelete

    or Stage1 + FullDelete

Both steps are located on the same microSD card already installed in the OBD module.

You must complete Step 1: AdBlue Block Reset first.

Do not start Step 2 until Step 1 is completed successfully and the Remaining Starts / AdBlue block message is cleared.

Step 1 — Reset the Engine Counter

Use the script named: Step 1: AdBlue Block Reset

This card is usually already installed in the OBD module.

Turn the Ignition ON

Turn the ignition ON, but do not start the engine.

Insert the key into the ignition and turn it to the second position.

The dashboard should turn on and all warning lights should appear.

Wait 20 Seconds

After turning the ignition ON, wait about 20 seconds.

This allows the vehicle control modules to wake up fully before the reset begins.

Plug in the OBD Module

Plug the OBD module into the OBD2 port under the dashboard.

Press the module firmly into the port to make sure it has good contact.

Select Step 1 on the Radio Screen

On the radio screen, select: Step 1: AdBlue Block Reset

Use the control knob to switch between the available steps.

Turn the control knob to select Step 1: AdBlue Block Reset, then press the knob to confirm your selection and start the process.

After selecting Step 1, watch the progress bar on the radio screen until it reaches 100%.

Follow the on-screen instructions during the process.

If the screen asks you to turn the ignition OFF or ON, follow the instructions exactly.

Do not remove the module while it’s downloading

The reset process usually takes 2–5 minutes.

Remove the Module

When the LED stops blinking or turns off, the reset process is complete.

Remove the OBD module from the OBD2 port.

Start the Engine and Check the Dashboard

Start the engine and check if the Remaining Starts message has disappeared.

If the message is still displayed, repeat Step 1 Reset 1–3 more times.

If the message does not clear after several attempts, do not continue to Step 2.

Send us the LOGFILE from the OBD module.

Youtube video
How to find and send the LOGFILE

Step 2 — Install the Delete Software

After Step 1 is completed successfully, continue with the main software installation.

On the radio screen, select the correct Step 2 script for your order:

  • Step 2: NoSCR
  • Step 2: Stage1 + SemiDelete
  • Step 2: Stage1 + FullDelete

Turn the Ignition ON

Turn the ignition ON, but do not start the engine.

Insert the key into the ignition and turn it to the second position.

The dashboard should turn on and all warning lights should appear.

Wait 30 Seconds

After turning the ignition ON, wait at least 30 seconds before plugging in the OBD module.

Plug in the OBD Module

Plug the OBD module into the OBD2 port.

Press the module firmly into the port to make sure it has good contact.

Select Step 2 on the Radio Screen

On the radio screen, select the correct Step 2 script for your order:

  • Step 2: NoSCR
  • Step 2: Stage1 + SemiDelete
  • Step 2: Stage1 + FullDelete

Use the control knob to switch between the available steps.

Turn the control knob to select Step 1: AdBlue Block Reset, then press the knob to confirm your selection and start the process.

After selecting Step 2, watch the progress bar on the radio screen until it reaches 100%.

Follow the on-screen instructions during the process.

If the screen asks you to turn the ignition OFF or ON, follow the instructions exactly.

Do not remove the OBD module during the installation process.

The software installation usually takes 3–5 minutes.

Remove the Module

When the LED stops blinking or turns off, the installation is complete.

Remove the OBD module from the OBD2 port.

Start the Engine

Start the engine and check the dashboard.

The OBD module installation is now complete.

If the Check Engine light appears after installation, this may be related to the SCR control unit.

When to Send the LOGFILE

Send us the LOGFILE if the installation does not complete successfully.

If an error occurs, the radio screen will display a message:

Exception. Read the LOGFILE

When you see this message, stop the procedure and send us the LOGFILE from the microSD card.

You should also send us the LOGFILE if:

  • The progress bar does not reach 100%
  • The LED keeps blinking for too long (10+ mins)
  • The Remaining Starts message does not clear after several reset attempts

You will need a computer and a microSD card reader to access the LOGFILE from the microSD card.

Youtube video
How to find and send the LOGFILE

Step 3 — Disconnect the fuse

After the software installation is completed successfully, the SCR fuse must be removed.

This step is required to prevent SCR / AdBlue-related warnings from coming back after installation.

The fuse box is located in the trunk, under the floor.

Before starting, review the fuse diagram and the photo of the fuse box location.

To remove the SCR fuse:

  • 1. Open the trunk.
  • 2. Lift the trunk floor cover.
  • 3. Locate the fuse box under the floor.
  • 4. Find the SCR fuse shown in the diagram.
  • 5. Carefully remove the fuse.
  • 6. Make sure the removed fuse is stored safely.

Once the SCR fuse is removed, the installation is complete.

Start the engine and check the dashboard. The DEF / AdBlue warnings and Remaining Starts message should no longer be displayed.

Full Installation Video: How to install SCR AdBlue / DEF Delete & PACKAGE DEAL

Youtube video
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HOW IT WORKS
FEEDBACK
3 min
Cutomer Support

How to contact us, what to send for faster help, and how we troubleshoot issues remotely

TO DO LIST
3 min
How to Prepare for Installation

Follow a simple checklist before you start: power, DEF level, PC tools, and radio/display notes.

HOW IT WORKS
6 min
How the Software Works

Learn what each system change does in the ECU and what mechanical work may be required