You are driving down the highway and suddenly your Mercedes-Benz displays a warning message "Collision Prevention Assist Plus Inoperative See Owners Manual".
Throttle response becomes very sluggish and the car feels like it has no power.
This is a problem reported by many 2015 and newer Mercedes-Benz C-Class, GLS-Class, E-Class owners.
Collision assists malfunctions can be caused by something as simple as low battery voltage but can also be an indication of a faulty Engine Control Unit (ECU).
Error message Mercedes Collision Prevention Assist Plus Inoperative See Owners Manual means that the system has malfunctioned.
COLLISION PREVENTION ASSIST PLUS monitors the traffic in front of the vehicle. If it determines that you are about to hit another car it will warn you with a message on the dashboard plus an audible sound.
With collision assist disabled your vehicle will no longer avoid a potential accident or automatically apply the brakes if you get too close to the vehicle in front of you.
Keep a safe distance from the vehicles in front of you and stay alert.
If the waring happened only one time and went away after restarting the vehicle, there may not be a reason to worry.
In most cases, you will experience one or two of these symptoms:
While getting this error once a year may not be a concern, you want to get the system diagnosed if the Collision Prevention Assist Plus Inoperative error keeps coming up periodically.
Find a safe location. Pull over, turn off the ignition, wait 2 minutes and restart the vehicle.
If the battery is partially discharged, you may need to let the car idle for at least 15 minutes before the error can be reset.
Inspect the front bumper for excessive dirt or ice.
Clean the bumper by removing any dirt that may be on the bumper or on the cross member that is mounted near the radiator.
Ask the dealer to perform a software update for the Collision Prevention Assist Module.
The dealer can tell you if there is a software update available that may fix your Collision Prevention Assist Plus Inoperative problems.
To diagnose this problem further you will need a scanner that can read and clear Mercedes-Benz specific fault codes.