The Mercedes Electronic parking brake is crucial to your entire driving experience. It not only allows you to park with ease. It is also crucial when driving as well. However, it will start working intermittently when faulty, which can be dangerous. The danger comes in when the parking brake applies, and releases as your car may start moving if parked on a slope.
Signs your Parking Brake is Malfunctioning
When your parking brake needs crucial repair, the “Mercedes-Benz Parking Brake Inoperative – See Operator’s Manual” message will appear after washing the car, driving in water puddles, or when it starts raining. It may also appear when the car moves or when you open the driver’s door.
Before the parking brake fully malfunctions, several warning signs may appear individually or simultaneously;
- Red parking brake warning on the 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 owner’s manual
- Noise when operating parking brakes.
Standard Mercedes Parking Brake Fixing Procedure
Before you can try troubleshooting, follow the steps below to try and fix your parking brake;
- Pull over and set the transmission to Park.
- turn off the ignition, then turn it back on.
- Pull the parking brake switch and hold it for 10 seconds, then release it.
- Start the engine to see if the light has turned off.
- If this does not work, proceed to the troubleshooting steps below.
Common Causes of Mercedes Parking Brake Problems
The most common cause of a faulty parking brake is a faulty actuator that is sticking; however, the issue can also be caused by faulty wiring, a dead battery, a faulty ABS module, or a faulty parking switch, among other issues.
Faulty Electric Parking Brake Module /Actuator
The Mercedes-Benz parking brake warning comes on when one of the rear electronic brake actuators sticks due to corrosion. This is a common problem in S-Class CL-Class, known as W221 and W216.
If you do not hear the parking brakes engage when you press the Park button, the electronic parking brake module or actuator/motor is faulty. Another symptom of a faulty parking brake motor is a loud, screeching noise when you try to apply or release the brake.
The parking actuators can get stuck over time if you rarely use the brakes. One possible solution is to use a Mercedes-Benz scanner and manually engage and repeatedly turn off the parking brakes at least fifteen times.
Solution:
- Removing both rear wheels and lubricating the parking brake using lithium-based spray penetrating lubricant will.
- If this does not work, replace the parking brake module or remove your faulty module and repair it.
To test the actuators;
- Press the Parking button on the dashboard. You should hear the electric motor engage.
- If you do not hear the noise in one of them, you know which one is faulty.
Note: Before replacing any parts, read the fault codes from the Electronic Parking Brake (EPB) module. If the parking brake malfunction shows on the dashboard, there is an incorrect code in the EPB module.
Go to Parking Module (EPB) > Actuations > Activate Parking Brakes to access the error code.
Damaged ABS Module
Corrosion or loss of connection at the ABS unit in the engine bay can also affect the parking brake. If the ABS module is faulty, the ABS light, traction control, and brake light will stay on. You will also get a parking brake malfunction notification message or error.
Solution:
- This issue needs to be diagnosed using a Mercedes-Benz scanner.
- You can take it to an auto shop for assistance or purchase a scanner and try to diagnose the issue yourself.
- If the ABS module is damaged, repair it if you can or replace it.
- However, in most cases, solving the issue is best handled by a professional certified by Mercedes.
How To Use a Scanner to Read Error Codes
The codes can be read from the EPB module. The principles stored in the EPB module will guide you in the right direction. For example, you will get fault codes such as:
- The position of the component Electric Parking Brake is Implausible
- B22d52- Electric parking brake malfunction; this component has not been implemented.
- B23aa07- The left brake has a malfunction and mechanical fault. The right brake caliper is faulty. An open circuit exists.
- B23aa77-the left brake caliper is malfunctioning, 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 troubleshooting the fault codes that read as CURRENT or PRESENT. Stored codes will help you figure out the underlying issue. A good scanner will allow you to check the operation of the parking brake motors and the parking brake switch without removing them.
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. The switch can trigger an electronic parking brake warning if the switch stays pressed.
Solution:
- Check to see if there is any debris causing the parking switch to stay pressed.
- Use a soft brush to clean the space around the switch.
- If this does not work, consider replacing the parking brake switch.
Note: Pay attention to the switch position. It should pull out when released. Ensure it doesn’t stay pressed when you release the parking brake button.
Weak Battery
A weak main battery can also cause the parking brake to be inoperative on a Mercedes-Benz. The parking brake relies on the battery to power its electric motor. If the battery is drained or old, the voltage to the motor won’t be enough to power the parking brake. A faulty charging system can also cause this problem.
Solution:
- Test the battery using the 12 Volt Battery Test Tool and charge or replace it if damaged.
- Also inspect the charging system and test its conductivity using a multimeter.
- Use a multimeter to measure the voltage of the charger’s output terminals.
- The voltage should be within the charger’s rated output voltage.
- If the charging system is damaged, repair or replace it.
- You can also visit a professional for assistance.
- Most auto parts stores will test the car battery free of charge.
Faulty Wiring
Electrical issues, such as faulty wiring or a blown fuse, can cause problems with your electronic parking brake. This is because they cannot transfer electricity or signals as they should.
Solution:
- Start by checking the fuse related to the parking brake system and replace them if they are damaged.
- Inspect the wiring and connections for any signs of damage or loose connections.
- If they are damaged, replace them.
- Or hire a professional mechanic to do the repairs if you do not have electrical know-how.
Damaged Brake Pads
Damaged brake pads will also cause a parking brake malfunction as they will not be able to engage as they should.
Solution:
- Inspect the brake pads for damage.
- If the brake pads are damaged, replace them and reset the parking brake.
- Refer to your owner’s manual for guidance.
- Alternatively, have a certified professional carry out the job.
Other Potential Causes
Here are other possible issues that can trigger the parking brakes error code. Refer to your Owner’s Manual to see the specific ones that apply to your car.
- 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.
Note: Some electronic parking brake-related issues can be specific to certain vehicle models. Refer to your vehicle owner’s manual or online repair guides for specific information about your car’s parking brake system.
Lastly, don’t hesitate to seek the assistance of a trained mechanic if you are unsure how to troubleshoot and fix the underlying issues causing your parking brake to malfunction.