Have the brake pads on your Mercedes R350 started squeaking? Does the brake pad warning light stubbornly remain lit on your dashboard? Replacing worn brake pads is essential for safe driving, but you can save money by replacing them yourself. However, you’ll need to reset that pesky brake pad warning light when the job is done. Don’t worry – resetting the brake pad sensor is straightforward when you know what to do. This guide will show you the easy process in seven simple steps so you can clear the warning light and be back on the road.
Here’s a quick answer:
To reset the brake pad warning light on a Mercedes R350 after changing the pads, locate the brake wear sensors behind each wheel and briefly press the button at the end of the sensor wire. Turn the ignition fully off and wait 10 seconds before restarting the engine. The brake warning light should now be cleared from the dashboard. Confirm by test driving above 25 mph and braking firmly several times.
Understanding the Brake Warning System
Modern Mercedes-Benz models like your R350 have a sophisticated brake pad wear monitoring system. Sensors in the pad hardware transmit data on the thickness of the pad material whenever you push the brake pedal. The system turns on the brake warning light when pads reach a thickness of 1.6mm, indicating it’s time for replacement. But even after new pads are installed, the light stays on until you complete a manual reset to notify the system that maintenance is now up to date.
Step 1: Turn the Ignition On
Unlike some resets, you don’t need to start the engine to reset brake sensors. Put your key in the ignition and turn it to the “on” position to power up the electrical system. Don’t start the engine yet. Verify that your parking brake is engaged before proceeding.
Step 2: Locate the Brake Sensor
We need access to the brake pad wear sensors to perform their reset procedure. On R350 models, you’ll usually find them attached to the back of the brake pad assembly, facing the rotor. They’ll be located behind the wheel on the outer brake pad. The button-like sensors have one exposed wire connected. Use your owner’s manual to verify sensor placement.
Step 3: Press and Release the Sensor
The small round button on the end of the sensor wire needs to be briefly pressed in, then released. This simulates a brake pad replacement to notify the system that new pads are now installed.
Important: Only press the sensor for a brief moment – about one full second. Holding it too long can damage the unit. You may need your flashlight to locate and access the button.
Step 4: Turn Off and Restart the Ignition
The system will not complete its reset sequence with the ignition still on. After pressing the sensor button on each brake assembly (one front, one rear), turn the ignition fully off. Wait about 10 seconds to allow system capacitors to discharge. Then restart the engine – the brake warning indicator should now be off!
Step 5: Test Drive to Confirm Reset
Sensor resets can be finicky, so confirm that the procedure fully cleared by test driving the vehicle above 25 mph. Apply firm pressure to the brakes several times, then check that the dash warning light remains off. Don’t neglect this step before considering the process complete.
Step 6: Reset Remaining Sensors
If you performed your last brake job in sets, sensors on the opposite wheels likely still show wear. You must clear all four sensors before the system considers maintenance complete. Follow Steps 2-4 to press and release the button for the remaining two sensors.
Step 7: Verify After Driving
Take your R350 for an extended test drive involving several instances of braking. If the brake warning light stays off, congratulations – you’ve successfully reset the system! But if the pesky lamp reappears, repeat the reset process to ensure a complete reset.
Why Reset Sensors Promptly
Clearing brake sensors isn’t just about turning off an annoying dashboard light – it keeps your brake system operating safely. The Mercedes-Benz pad wear monitor system actively modulates brake pressure based on available pad thickness. Failure to notify it of new pads can reduce system pressure capacity. Resetting sensors promptly is crucial for restoring full braking ability after new pads are installed.
Reset Anytime Pads are Replaced
For the safest operation of your R350’s advanced brake systems, the reset procedure should be performed anytime brake pads are replaced, not just when warnings first appear. The system relies on accurate data to work properly. Taking a few quick minutes for a sensor reset with every pad swap keeps your vehicle’s lifesaving brake system performing at its engineered best.
While Mercedes models feature some of the most sophisticated brake systems around, drivers still bear responsibility for proper maintenance. Resetting wear sensors keeps the computer informed so your safety isn’t compromised. With the simple seven-step process outlined here, you can clear brake warnings quickly and rest assured your R350 will stop safely time after time.
1. Do I need any special tools to reset the brake sensor?
No, the reset procedure does not require any special service tools. All you need is the ignition key and simple access to the sensors behind the wheels.
2. How can I tell if my brake pads need replacement?
In addition to the brake warning light, listen for high-pitched squealing when braking. Also check pads visually through the wheel for thin pad material. Most pads need replacement at 2-3 mm thickness.
3. Why won’t the brake warning light turn off after a sensor reset?
All four sensors must be reset – front and rear, left and right. The light stays on if any sensor still detects thin pads. Make sure all sensors are reset properly after new pads are installed.
4. My dashboard shows an error code instead of the brake light. What should I do?
Diagnostic trouble codes indicate a fault in the electronic monitoring system. The sensor reset procedure may clear many errors. But some faults require analysis by a Mercedes-Benz technician.
5. How often should I expect to change brake pads on my R350?
Mercedes brake pads typically last 30,000-70,000 miles depending on your driving habits and style. Annual brake inspections help spot wear early. Pads must be replaced when material gets dangerously thin for safe braking.