Brake pad life screen

[dishdude]

I was in a rental Silverado - sweet truck btw, comfortable and drove great. I was on some pretty desolate roads in Idaho that had great visibility and the truck cruised at 95-100 like it was nothing. I was amused by two things with the truck, a screen that displayed the brake life as a percentage and this was the first vehicle I've driven with auto start/stop that also had an oil pressure gauge.

I want to know how this brake pad life gauge works. Is it just a guess or is there some sensor in the pad?

 

[charbaby]

Hmmm, interesting!
I wonder if it measures pad usage similarly to an oil life monitor measures % of oil life remaining?...# of start-up/shut-offs, miles traveled, duration of trips, length of time, etc., etc.

* How many number of stops you make
* How long the brake pedal is depressed
* Or is it tied in with the ABS sensor and somehow measures mm of pad remaining
* etc., etc.

 

[IveBeenRued]

Very cool. My guess is there is a sensor somewhere on the caliper that measures how extended the piston is.

My hat is off to GM for this one; this increases the safety factor for consumers. But I’m sure their stealerships will be cursing this feature as unnecessary brake jobs at hyper inflated prices are a very common upsell when vehicles are in for other services (not GM bashing, this goes for all brands).

 

[skyactiv]

 

[MrHorspwer]

The "sensors" clip onto the brake pads. I say "sensor" because it's really only a couple resistive circuits. Each sensor has three circuits in it. Two of these circuits have a resistor on them and one does not. As the brake pad wears, the circuit in the sensor grounds out on the rotor. Through each resistor, the ABS module will see a different signal voltage for each of the three, which is equated to brake pad wear. They are also only on the left side of the vehicle, front and rear.

On the cluster, brake pad wear is estimated as a percentage. The initial brake pad wear is a true estimation based on brake application. Once the first part of the sensor is grounded, meaning 30% of the pads have been worn, that wear rate is taken into account in the calculation until the next part of the sensor is grounded, and so on.

When the last portion is grounded, the pads need to be replaced. You'll get a message on the cluster and the screen will change from a percentage to a mileage. I think the default when the last part of the sensor hits is 2,000 miles pad life remaining. It will count the milage down while continuing to give messages that the pads need to be replaced until the pads life system has been reset.

There is also a method in the cluster to disable the system if your aftermarket pads don't have provisions to mount the sensors or don't include new sensors (which are also a wear item and need to be replaced with the pads).

FWIW, list price for a new sensor is $24.

 

[demarpaint]

Great idea if it works.

 

[RamFan]

Very, very, cool feature.

The Alfa has a wear sensor that trips once a certain amount of pad has worn off, but it would be really nice to have a gauge showing the percentage such as this.

 

[JohnnyG]

Both of my old Cadillacs ('99 &'08) had the brake pad replacement warning. Wagner aftermarket pads had the sensors included. Back then I know they were on both front pads, never messed with the rears. The Mercedes has them also. In one case, GLC, it is on the right front pad, and again, not sure about the rears.
These are all the simple "open circuit" sensors that display a dash warning light.

 

[KGMtech]

VW did it simpler with a wire that wore through when the pads got to a point, then a warning message on the dash, The wire was imbedded into the pad material.

 

[joekingcorvette]

Wow that is very impressive!

 

[mightymousetech]

Very cool. My guess is there is a sensor somewhere on the caliper that measures how extended the piston is.

My hat is off to GM for this one; this increases the safety factor for consumers. But I’m sure their stealerships will be cursing this feature as unnecessary brake jobs at hyper inflated prices are a very common upsell when vehicles are in for other services (not GM bashing, this goes for all brands).

Looks just like the same sensor the Germans have been using forever. So until the one pad with the sensor is worn down to min, any calculation is a complete guess by the vehicle.

BMW has actually done away with “estimate percentage remaining” as it is completely inaccurate. Now you just get a warning when the sensor trips.

 

[wings&wheels]

Struggle to think why I'd need this level of detail...but, hey it sells

I like the European wire in a hole in the pad sensors which indicate when you have maybe 20-15% of pad left. Simple, effective, though I tend to not ever let them get that far.

 

[Dave9]

Just another thing to break. Checking pad thickness only takes a second on modern alloy wheels with their big openings between spokes. Okay add two minutes to check the back side, while you're inspecting your suspension which you should be doing anyway.

 

[tc1446]

My '18 uses this type sensor: https://www.brembostoreusa.com/product/disc-brake-pad-wear-sensor/A00353
Still on OEM's at 49K; tire tech said pads still look good.

 

[Kruse]

I’m curious how the feature will hold up in the salt belt.

 

[Dave9]

Just another thing to break. Checking pad thickness only takes a second on modern alloy wheels with their big openings between spokes. Okay add two minutes to check the back side, while you're inspecting your suspension which you should be doing anyway.

I didn't even think of the OTHER angle to this. What if goverment or an automaker, in an effort to Look Out For Your (their) Best Interests, decides that if the sensor reads 0 life left (whether it be due to brake pads worn or the sensor/wire/whatever malfunctioning), that the vehicle will no longer be driveable, that it either won't start or goes into a crippled mode while driving due to a faulty sensor circuit? That might Save A Life, or... it might cost one, or be a major PITA for many people trying to save one person who can't bother to check their vehicle every now and then, and still ends up dead because of something else they failed to exercise due diligence to keep up on.

Just sayin', a sensor on this subsystem, pummeled by road debris/rain/salt/etc and brake heat, seems like a sensor that may not last the life of a vehicle and GM has never been known to pay a lot of attention to longevity of their designs. Currently I consider them 10 yr, 100K mi vehicles before problems. I mean any built in the last decade, that their golden years ended closer to 20 years ago.

 

[64bawagon]

In the salt belt the corrosion will destroy the rotors and pads long before the friction material wears out.

 

[SammyChevelleTypeS3]

The "sensors" clip onto the brake pads. I say "sensor" because it's really only a couple resistive circuits. Each sensor has three circuits in it. Two of these circuits have a resistor on them and one does not. As the brake pad wears, the circuit in the sensor grounds out on the rotor. Through each resistor, the ABS module will see a different signal voltage for each of the three, which is equated to brake pad wear. They are also only on the left side of the vehicle, front and rear.

On the cluster, brake pad wear is estimated as a percentage. The initial brake pad wear is a true estimation based on brake application. Once the first part of the sensor is grounded, meaning 30% of the pads have been worn, that wear rate is taken into account in the calculation until the next part of the sensor is grounded, and so on.

When the last portion is grounded, the pads need to be replaced. You'll get a message on the cluster and the screen will change from a percentage to a mileage. I think the default when the last part of the sensor hits is 2,000 miles pad life remaining. It will count the milage down while continuing to give messages that the pads need to be replaced until the pads life system has been reset.

There is also a method in the cluster to disable the system if your aftermarket pads don't have provisions to mount the sensors or don't include new sensors (which are also a wear item and need to be replaced with the pads).

FWIW, list price for a new sensor is $24.

Does it sound like a waste? Brakes are not brain surgery. Even non mechanical people are usually smart enough to ask their mechanic when they need overhaul. I guess the world is gearing up for a population who does not know how to do anything for themselves any more. We had a highly educated "Doctor of Engineering" at work who could not even figure out how to get to / let alone replace his flat tire with the spare. We did it for the poor guy. His parents bought him a brand new car for Christmas each year! Some lucky folks at the plant bought a few off of him before he was tranfered and got his automatic promotion up the ladder to management.

 

[RooflessVW]

Imagine thinking that more information available to the driver is a bad thing.

 

[The Critic]

Imagine thinking that more information available to the driver is a bad thing.

Tech: your rotors are horribly rusted and the pads are seized in the caliper brackets. You need a brake job.
Customer: my car says I have 80% brake life remaining you, are trying to rip me off!!!