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Faulty handbrake module or Parking Brake mechanism may fail triggering Mercedes-Benz Parking Brake Inoperative  See Owner's Manual Warning on the dashboard. 

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Mercedes-Benz Electronic Parking Brake (EPB) See Owner's Manual in most cases comes on because the parking brake actuator at one of the rear wheels is sticking.


Mercedes-Benz Parking Brake Inoperative - See Operator's Manual comes on during heavy rain or when you drive through water puddles or mud. Parking brake inoperative messages may appear after a car wash.

Mercedes-Benz parking brake warnings may also appear when the vehicle is in motion, and the driver's door is opened. The parking brake may automatically apply and then release. 


Mercedes Parking Brake See Owners Manual
  • Red parking brake warning on dashboard
  • Both the red and the yellow parking brake symbols may come on 
  • Parking brake icon flashing in the instrument cluster
  • Parking Brake – See Operator’s Manual
  • Parking Brake Nonfunctional – Visit Workshop
  • Electronic parking brake malfunction see owners manual
  • Noise when operating parking brakes. 

Temporary Fix

Pull over and set the transmission in Park. Please turn off the ignition, then turn it back on. Pull the parking brake switch and keep it pulled for 10 seconds, then release. Start the engine, and the light, in most cases, will turn off. 

Here is a list of common problems that cause the Parking Brake See Owner's Manual warning to stay on.

The Mercedes-Benz parking brake warning comes on when one of the rear electronic parking brake actuators sticks due to corrosion.

Removing both rear wheels and lubricating the parking brake using lithium-based spray penetrating lubricant will, in most cases, fix the problem. 

Common Causes

The parking brake inoperative problem is common on Mercedes-Benz models with electronic parking brakes such as the S-Class, GL-Class, and most 2015 or newer models. 

The problem can also be the motor inside the electronic parking brake (behind the rear brake caliper) which can also break and trigger the Parking Brake. See Owner's Manual. 

Electric parking brake module /actuator


If you have applied the parking brakes a few times, you should be familiar with the sound on parking brakes being applied.

If you don't hear the parking brakes engage when you press the Park button, the electronic parking brake module or actuator/motor. Another symptom of a faulty parking brake motor is a loud, horrible screeching noise when you try to apply or release the brake.

Bad Mercedes parking brake actuator caused parking brake inoperative fault

This is a common problem, for example, in S-Class CL-Class, known as W221 and W216, respectively. You can replace the parking brake module or remove your faulty module and send it for repair to any of these companies that offer this repair service on eBay. 

ABS Module 


Corrosion or loss connection at the ABS unit (in the engine bay) can also trigger this problem.

If the ABS module is faulty, you will also notice ABS light, traction control, and brake light (staying on), along with the parking brake malfunction. While not a very common problem, this issue needs to be diagnosed with a Mercedes-Benz scanner. 

Faulty Parking Brake Switch 


Parking brake switches may stick and not release fully. The parking brake switch is located under the headlight switch on the dashboard. 

Pay attention to the switch position. It should pull out when released.

If the switch stays pressed, it can trigger an electronic parking brake warning. Make sure that every time you release the parking brake button, it doesn't stay pressed.

Weak Battery

Bad battery park brake inoperative

A weak main battery can also cause the parking brake to be inoperative on a Mercedes-Benz. Most auto parts stores can test your car battery free of charge, or you can perform a battery test yourself using the 12 Volt Battery Test Tool. 

Less Likely Problems

corrosion electronic parking brake

Other possible issues that can trigger Parking Brake See Owner's Manual. 

  • Low main battery voltage.
  • Faulty SAM or Central Gateway Module. 
  • Damaged wire harness.  
  • Software issue - Ask the dealer to perform an update. 
  • A loose, broken, or corroded connector at the parking brake actuator.
  • The brake light switch is faulty.
  • ABS wheel speed sensor defective or dirty.
  • Faulty parking brake switch. 
  • Brake cables need adjustment if they are not pulling evenly. 


One quick test you can perform is to press the Parking button on the dashboard and have a friend listen to the rear wheels. You should hear the electric motor engage. Check both rear wheels. If you do not hear the noise in one of them, you know which one is faulty. 

If you rarely use the parking brakes, the parking actuators can get stuck over time. One possible solution is to use a Mercedes-Benz scanner and manually engage and disable the parking brakes at least fifteen times repetitively.


Before replacing any parts, it is important to read the fault codes from the Electronic Parking Brake (EPB) module. If the parking brake malfunction showed on the dashboard, there is a faulty code in the EPB module. 

Diagnose Mercedes Parking Brake

Go to Parking Module (EPB) > Actuations > Activate Parking Brakes. 

Use a Mercedes-Benz scanner to read fault codes from the EPB module. The codes stored in the EPB module will guide you in the right direction. For example, you will get fault codes such as:

  • The position of component Electric Parking Brake is Implausible
  • B22d52- Electric parking brake malfunction; this component has not been put in position.
  • B23aa07- The left brake has a malfunction, mechanical fault. The right brake caliper is faulty. An open circuit exists.
  • B23aa77-the left brake caliper has a malfunction, and the commandment position cannot be reached. The left brake caliper is faulty. An open circuit exists.
  • 584F - CAN signal WHeel Speed From Control Unit N47-5 ESP Control Unit is Implausible
  • 5160 - CHeck Mechanical Components For Proper Operation and Installation. 

Continue the troubleshooting based on the fault codes that are showing as CURRENT or PRESENT. Stored codes can be an indication of an intermittent issue. 

Once you read the fault codes with a Mercedes-Benz scanner, you will have a better idea of what's wrong with the car and the cause of the Parking Brake being Inoperative. See the Owner's Manual Warning. With a good scanner, you will be able to check the operation of the parking brake motors and the parking brake switch without removing them. 

External References

  1. Parking Brake See Owners Manual - A-Class
  2. Mercedes-Benz C-Class Parking Brake Warning -
  3. Mercedes Parking Brake See Operator Manual -