A pressure indicating valve cap for mounting on a valve stem of a vehicle tire

A pressure indicating valve cap (10) suitable for mounting on a valve stem of a valve of a vehicle tire, the valve cap comprising a housing assembly (12,14,16,18,20) bounding a central valve stem receiving space (22) and a battery receiving space (32), the housing assembly accommodating a printed circuit board (34) with a pressure sensor (36), a central processing unit (CPU), a memory, and pressure fault signaling means (38), wherein the CPU is configured to measure a reference pressure value (p reference ) when the pressure indicating valve cap (10) is screwed onto the valve stem and to store that in the memory, and to repeatedly measure an actual pressure value (p actual ) and to compare the actual pressure value with the reference pressure value and with each comparison establish whether the comparison indicates a pressure value change that is larger than a threshold factor times the reference pressure value and in the affirmative activate the pressure fault signaling means (38).