Principles Of Operation
WARNING: This page is about a different car, the 2011 Jaguar XKR, 2011 Jaguar XK, 2010 Jaguar XKR, and 2010 Jaguar XK. However, it is still accessible from the selected car via links, so may be relevant.
When hydraulic pressure is supplied to the caliper, the piston extends to force the inner pad against the brake disc. The caliper reacts and slides along two guide pins to bring the outer pad into contact with the brake disc.
When a brake pad incorporating a brake pad wear sensor is approximately 75% worn, the brake pad wear sensor goes open circuit. When the instrument cluster detects the open circuit, it illuminates the amber light emitting diode (LED) in the brake warning indicator, displays an appropriate warning in the message center and sounds a warning chime. Refer to Instrument Cluster - DESCRIPTION AND OPERATION .