The first thing you need to do is pull over as soon as it is safe to do so and do the following: 

• clean the radiator grille
• restart the engine 
• reactivate the Distronic Plus

If these steps don't restore the Distronic Plus operation, one of the following problems has caused the system to malfunction. 

Possible Causes

The most common problems that cause the Distronic Plus to malfunction include:

• Distronic sensors at the front of the vehicle are dirty
• Heavy snow or rain
• Dirty or scratched camera lens
• The radar sensor system is temporarily inoperative due to electromagnetic radiation emitted by nearby TV or radio stations or other sources (that is normal. restart the engine)
• The system is outside the operating temperature range
• On-board voltage is too low (warning tone also sounds) it might be bad battery, alternator, or electrical system issues
• The system has not detected any other vehicles on the road for a very long period. 
• Incorrect tire sizes or pressures
• Wheel speed sensor error

To find out what is wrong with your Distronic Plus, you will need to read the fault codes from that module. 

DISTRONIC PLUS is operational again, and the display message may disappear when:

• The dirt drops away while the vehicle is in motion
• The system detects that the sensor is fully available again
• The system is within the operating temperature range.
• You clean the sensors in bumpers that might be dirty
• You clean the DISTRONIC PLUS cover in the radiator grille
• Wait until the system cools down or the battery recovers 
• Restart the engine

Try activating DISTRONIC PLUS again later

How to Diagnose Mercedes Distronic Problems

Cleaning the sensors may not fix the problem. To find out why your Distronic Plus is not working, you must read the Distronic control unit's fault codes. 

1. Get a Mercedes All System Diagnostic Scanner. Generic OBD2 scanners will not be able to diagnose the Mercedes-Benz Distronic system. 
2. Plug the scanner into the diagnostic port under the dashboard. 
3. Turn on the ignition that should turn on the scanner. You don't need to start the engine. 
4. Select your Mercedes model from the main menu. 
5. Select Control Units from the menu. 
6. Scroll down until you see Distronic Plus and press enter. 
7. Scroll down to Read Codes from the menu and press enter. You will get a code and a short description of the problem. 

Related Messages

• Distronic Plus Currently Unavailable See Oper. Manual 
• Distronic Plus Inoperative