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By YOUCANIC on May 12, 2019

BMW Brake Pad Wear Sensor Replacement

In this guide, we focus on how to replace BMW brake pad wear sensor operation, how to reset brake warning light & message, the pros, and cons of bypassing the sensor and more. 

This guide focuses only on the brake wear sensor and assumes you have already replaced the brake pads. 

All 2000 and newer BMW including 1, 3, 5, 6, 7, 8, X1, X2, X3, X4, X5, X6, Z3, Z4, i8 and M series have at least two brake wear sensors. Most BMWs have one sensor for the front brakes (installed on driver side pads) and one sensor for the rear brakes (installed on passenger side brake pad). 

Symptoms of worn brake sensor

The following message may remain on the instrument cluster even when you replace the brake pads. 

bmw brake light on

Brake Warning Light On Dashboard

bmw idrive message due to worn brake pads or bad wear sensor

iDrive Message: Brake Pads are worn to the minimum depth. Have the pads replaced by the nearest BMW center.  

bmw car on lift

Service Vehicle Symbol with car on lift .

Replacement Cost 

The average price to replace BMW wear brake sensor ranges between $6 and $30 when you replace the sensor yourself.

The typical cost to change BMW brake sensor at the dealer or mechanic ranges between $65 and $120.

replacement bmw brake wear sensor

  BMW Brake Wear Sensor

 

Replacing  BMW brake wear sensor is a very easy procedure and takes less than 30 minutes.

Follow the instructions in the next section to learn how to replace the sensor yourself. 

What you will need

Instructions

  1. Determine if you are replacing front or rear brake pad wear sensor. remove bmw wheel to replace bmw brake wear sensor

     

  2. Jack up the vehicle and remove the wheel. If replacing front brake pad sensor, jack up the driver's side wheel. If replacing rear brake pad sensor, jack up passenger side wheel. Remove the wheel from the vehicle. get ready to change bmw brake wear sensor

     

  3. Locate the brake pad wear sensor on the brake pad. bmw brake pad wear sensor location

     

  4. Use a flat head screwdriver to pry out the old sensor.remove bmw brak sensor

     

  5. Unhook the sensor from the brake caliper release valve. brake pad wear sensor wire bmw 1 2 3 4 5 6 7 x1 x3 x5 z3 z4 series

     

  6. Unhook the sensor wire from the strut bracket by pulling it out of the bracket. 
  7. Open the black box mounted on the wheel well. Inside you will find the connector. BMW BRAKE PAD SENSOR CONNECTOR

     

  8. Pull the connector out of the box. Press the release tab on the connector and separate the wires. BMW BRAKE WEAR SENSOR WIRE

     

  9. Install the new sensor in reverse order. NEW BMW BRAKE SENSOR

     

Reset BMW Brake Pad Wear Reminder

There are two methods to reset BMW brake wear sensor. 

Method 1: Reset BMW Brake Pad Sensor via Instrument Cluster

This video shows you how to reset BMW brake light service reminder using the buttons on the instrument cluster. 

Instructions

  1. Turn ignition on but do not start the car. 
  2. Press and hold the reset button on the side of the dashboard. 
  3. After a few seconds, you will see the service menu at the center of the dashboard. 
  4. Press the reset button several times until you see the symbol for the front of rear brakes. 
  5. With the brake symbol on small LCD, press and hold the reset button until you see the words RESET. 
  6. When RESET displays on the screen, release button and press it again for about 5 seconds to reset the brake light. 

 TIP

If the reset procedure is carried out successfully, the brake symbol in the small LCD will turn from RED to ORANGE. 

Method 2: Reset BMW Brake Light with an OBD-II Scanner

Another method to reset BMW brake warning is to use a scan tool.

Many OBD-II scanners allow you to access the Condition Based Serving (CBS) menu and reset the brake mileage limit.

If you have tried method 1 but have been unsuccessful, the next step is to use a scanner.

In addition to resetting the brake light, a good scanner allows you to read fault codes from DSC module and determine why the brake light won't reset.

 

In this case, we are using Foxwell Scanner for BMW but other scanners offer this functionality. Learn more about OBD-II scanners that access multiple systems on BMW cars.

How does the brake pad wear sensor work?

BMW brake wear sensor is nothing more than a wire that runs at the tip of the sensor. 12-volt typically feeds the sensor at all times.

Once the brake pads wear out, the tip of the sensor where the wire runs is cut as well which open the circuit.

The brake or DSC module will see that from no resistance now there is an open circuit at the sensor triggering a fault code such as 5F12, 5F13, 5F14, 5F14, 5F16. 

Examples: 

  • 5F12 DSC Brake pad wear, front axle, brake pads
  • 5F15 DSC Brake pad wear, rear axle plausibility. 

Many owners wonder what is the sensor resistance for the brake pad sensor.

The brake system simply checks is there brake sensor is an open circuit (worn brake pad) or closed circuit (good brakes).

Brake Pad Sensor Bypass

Many BMW owners choose to bypass (delete) the brake wear sensor by removing the sensor and installing a clip or cutting the sensor wire, exposing the wires and connecting them together.

This is known as short-circuiting the wire and emulates a "good" sensor but is not recommended. 

bypass bmw brake sensor

 CAUTION

It is not recommended to permanently disable BMW brake pad wear sensor. If you bypass the brake pad wear sensor you will NOT know when your brakes are due for replacement. Your brake pads will wear completely until they reach the metal part at which point you will have metal on metal contact. Not only will your braking be reduced, you will also hear a grinding noise and your rotors will get damaged and require replacement as well. 

Frequently Asked Questions 

How many BMW brake pad sensor?

  • Typically two. One sensor is located on one front brake pad (left front). The second wear sensor is on the right rear brake pads

What is BMW brake pad sensor resistance?

  • New Brake Pads: Zero resistance (or closed circuit). 
  • Worn Pads: Infinity ohms ( open circuit) when the pads (sensor) wear out. 

Where is the BMW brake pad sensor located? 

  • Front left brake caliper. Mounted on the brake pad.
  • Rear right brake caliper. Mounted on the brake pad.
Vehicle

Feedback

Profile picture for user Vicki Swan
David R Smith,…, 2019-06-03

The pad wear sensors on BMW vehicles newer than 2003/2004 are not a simple short circuit wire that can break with pad wear and cause an open circuit. Rather BMW uses a "two-step" wear sensor made by Bosch. The epoxy housing of this two-wire Bosch sensor contains two physical resistors wired in parallel. Let's call the two separate resistors R1 and R2. R1 is a 0 ohms resistor and R2 is 270 ohms. Each resistor has a small connecting wire that runs physically close to the wear tip of the Bosch sensor. The wear tip rubs against the rotating brake disk as the pads wear down. This rubbing gradually sands away the protective epoxy end of the wear tip and eventually breaks the small wire connected to R1. With even more pad wear and more sanding down of the wear tip, the second wire connected to R2 also eventually breaks. The Bosch sensor is designed so that at about 50% pad wear, the wire to R1 breaks and at about 15% remaining pad, the wire to R2 breaks. This wire breaking is referred to as sensor triggering since Brake Pad Warning Messages are triggered. When R1 triggers, the BMW senses the first stage of pad wear and sends out an polite Pad Wear Notification early warning message that the pads are wearing. But typically the pads still have many thousand miles left on them. When R2 triggers BMW sends a very stern safety warning to change the pads immediately! When the Bosch sensor is new or only lightly worn, the overall two-wire sensor will measure 0 Ohms with an ohmmeter since R1 dominates the reading. When the R1 does trigger, it effectively becomes an open circuit resistance leaving the 270 ohms R2 load across the external wires. After more pad wear, R2 will eventually trigger, and the external sensor wires will measure infinite Ohms (an open circuit). At this point after R1 and R2 have both triggered, Users typically have several hundred more miles left but the pads are pretty thin and User runs the risk of damaging the brake disks.or even the calipers with continued usage. In summary: A new Sensor measures 0 Ohms, after R1 triggers, it measures 270 Ohms, after R1 and R2 are both triggered, it measures infinite ohms (open circuit).

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