Camshaft Profile Switching

WARNING: This page is about a different car, the 2015 Jaguar XK, 2014 Jaguar XK, 2013 Jaguar XK, and 2012 Jaguar XK. However, it is still accessible from the selected car via links, so may be relevant.

The CPS (camshaft profile switching) system switches the intake valves between two cam profiles which have different lift and period. The low lift profile improves driveability and emissions at lower engine speeds. The high lift profile improves power and torque output at higher engine speeds.

The intake camshafts have three lobes for each valve. The two outer lobes have identical profiles that produce the high lift of 10.53 mm (0.415 in.). The central lobe produces the low lift of 5.50 mm (0.217 in.). Switching between cam profiles is performed by a switchable tappet on each intake valve. The switchable tappets are operated by engine oil controlled by a CPS solenoid on each cylinder head. Operation of the CPS solenoids is controlled by the ECM.