MErroneous "Service due" Message Though Brake Lining Thickness Sufficient. The CBS data calculated for the remaining distance of the front and/or rear brake pads does not agree with the actual brake pad thickness. The yellow brake lining service due indicator illuminates even though the pad thickness is greater than the minimum wear limit (approximately 3.7 mm); the brake wear sensor has not yet been activated (from a thickness of approx. 4.2 mm). In some cases, the red warning message may already be active. The CBS front/rear brake display is based on a mathematical calculation. Various influences are incorporated into this calculation (for example, vehicle speed, brake pressure, and rotor temperature). Due to changing driving characteristics and/or unfavorable environmental conditions, the calculated remaining distance may differ from actual pad thickness.