[jetblackcoupe]

so my rear brakes are due soon, but something weird happened today.. my "BRAKE" light came on and when i check the service reminders it says my front brakes are due in ------ miles.



i know that my front brakes have a few thousand miles left so it's definitely wrong. would it be a faulty sensor or something?

[Efthreeoh]

I doubt it's wrong. How do you know the fronts have a few thousand miles left? When the "Brake" indicator comes on it's because the wear sensor has broken through the second wire loop and the sensor is at the rotor face. Also, once the light comes on you can go a few thousand miles before the pads need to be replaced anyway. It is not uncommon for these cars to need all four brakes at the same time. My car needed all four bakes the first time through them and needed the rears about 2,500 miles past the fronts on the second go round.

If you are going to DIY them, then why not just do all four at the same time anyway. The tools are out and the car is up in the air.

[jetblackcoupe]

Originally Posted by Efthreeoh

I doubt it's wrong. How do you know the fronts have a few thousand miles left? When the "Brake" indicator comes on it's because the wear sensor has broken through the second wire loop and the sensor is at the rotor face. Also, once the light comes on you can go a few thousand miles before the pads need to be replaced anyway. It is not uncommon for these cars to need all four brakes at the same time. My car needed all four bakes the first time through them and needed the rears about 2,500 miles past the fronts on the second go round.

If you are going to DIY them, then why not just do all four at the same time anyway. The tools are out and the car is up in the air.

I'm positive it's wrong. The fronts had 5-6000 miles left and the rears had 500. I bought rear components and then all of a sudden yesterday the front warning goes off and it's not telling me it's due in 1000 or 500 it's telling me it's due now.. Can't be right?

[ssmith96]

I think if it can't estimate then something must have happened to the sensor... get the pads visually inspected for pad life and then if you need just have a new wear sensor installed

[Efthreeoh]

Originally Posted by jetblackcoupe

I'm positive it's wrong. The fronts had 5-6000 miles left and the rears had 500. I bought rear components and then all of a sudden yesterday the front warning goes off and it's not telling me it's due in 1000 or 500 it's telling me it's due now.. Can't be right?

It can. You are looking at it backwards; the mileage in the CBS is only an "estimate" and can be less precise than reality. The sensor is mechanical and is always correct and is reality. Once the second loop of wire breaks in the sensor because the sensor is in contact with the rotor face and wears through the wire, the indication light comes on and remains on until you change the pads and replace the sensor (and manually reset the CBS).

The CBS estimates the remaining mileage (pad life) by using a predetermined brake wear calculation AND actual wear rate information from the sensor. The sensor is dual stage, which means it has two loops of wire in it. When the 1st wire breaks, the CBS uses that event to compare the actual wear of the pads to the predetermined wear rate in the CBS computer and adjusts the calculated estimate going forward accordingly to more precisely predict when the pads will wear out. However, the CBS assumes that the car will be used pretty much in the same use pattern leading up to the 1st wire breakage event. If the use of the car after the 1st wire breakage event is not consistent with that prior to the event, then the mileage estimate can be slightly incorrect. So for example, if you take a few long trips on the highway or start driving in more stop and go urban traffic, or start driving more aggressively, the CBS estimate can be off by a few thousand miles.

If you are not the original owner, and the car is still on the original brakes, then what I said above is even more the correct explanation. If the car had a previous owner that drove the pads though the 1st wire break event, then you took the car over after the wire broke, your driving pattern will definitely be different, than the previous owner and would change the precision of the CBS's calculation of the remaining miles estimate.

[Red_Bean_Bun]

Physical inspection is recommended .....

[mike3000fl]

This guys gets it... CBS is a guess based on usage. Sensor is real time warning that you are at the end of brake pad life.

Originally Posted by Efthreeoh

It can. You are looking at it backwards; the mileage in the CBS is only an "estimate" and can be less precise than reality. The sensor is mechanical and is always correct and is reality. Once the second loop of wire breaks in the sensor because the sensor is in contact with the rotor face and wears through the wire, the indication light comes on and remains on until you change the pads and replace the sensor (and manually reset the CBS).

The CBS estimates the remaining mileage (pad life) by using a predetermined brake wear calculation AND actual wear rate information from the sensor. The sensor is dual stage, which means it has two loops of wire in it. When the 1st wire breaks, the CBS uses that event to compare the actual wear of the pads to the predetermined wear rate in the CBS computer and adjusts the calculated estimate going forward accordingly to more precisely predict when the pads will wear out. However, the CBS assumes that the car will be used pretty much in the same use pattern leading up to the 1st wire breakage event. If the use of the car after the 1st wire breakage event is not consistent with that prior to the event, then the mileage estimate can be slightly incorrect. So for example, if you take a few long trips on the highway or start driving in more stop and go urban traffic, or start driving more aggressively, the CBS estimate can be off by a few thousand miles.

If you are not the original owner, and the car is still on the original brakes, then what I said above is even more the correct explanation. If the car had a previous owner that drove the pads though the 1st wire break event, then you took the car over after the wire broke, your driving pattern will definitely be different, than the previous owner and would change the precision of the CBS's calculation of the remaining miles estimate.

[jetblackcoupe]

I'll get them inspected but I'm still skeptical despite the good explanations

[MasterWang]

My light came on about 3 weeks ago (brake light + red car on lift symbol).
For quick visualization without removing the wheels, I stuck my iPhone through the wheels and took a picture of the pads with the flash on. Replacing them tomorrow using these DIY videos.

Fronts:

Rears:

[mike-y]

seriously, get out of your car, and LOOK at the pads. Lots of cars don't have brake sensors, and that's how you check the pads - you look at them.


If they are thin like Masterwong's pic above, you need to replace them.

[VTECaddict]

Your pads are gone. The mileage before was only a rough estimate.