The 2019 Cadillac CT6 big luxury sedan is gaining a new interesting feature that could be General Motors’ first application of electrical brake pad wear sensors. The feature will be standard on models with electro-hydraulic brake system, including the ones packing either a 2.0-liter turbo I4 or a 4.2-liter twin-turbo V8.
Electrical brake pad wear sensors have been used extensively in the automotive industry since more than forty years ago. If you’re familiar with German cars, you will likely be familiar with the sensors as well.
These sensors usually come with a modest design, having a conductive metal loop placed in the pad, which carries some current when the car is driven. As soon as the pad wears thin, the loop will begin to be exposed to the brake rotor, causing an increased resistance and a brake warning light to illuminate on the instrument cluster, telling the driver that the pads are due to change.
There are actually more advanced electrical brake pad wear sensors that use a couple of loops at two separated depths. This will allow the car to estimate how long the pad can still be used instead of just warning the driver as it wears out.
It’s kind of unbelievable that such an easy-to-implement, decades old technology has never made its way into a GM car before the 2019 Cadillac CT6. GM and many other carmakers prefer to use an even simpler solution, namely a clip that generates a squeaking noise after the pad material has worn enough. It’s preferred because it’s simple, low-cost, and good enough to warn most drivers.
Both the noise-generating pad wear indicator and the electrical sensor fall under the category of disposable technologies, which means that they must be replaced every time the pad is changed. Fortunately, neither of them are expensive, and Cadillac has been hard at work to reduce the cost as much as possible by equipping the CT6 sedan with only two electrical pad wear sensors.