Nissan Primera Alarm Fault (motion sensing)

I've got the same car and can confirm the Haynes omissions. I've got a U.S. G20 manual and their alarm system doesn't seem to use motion sensors so that's no help. I doubt that cleaning the sensors will do much as they are ultrasonic detectors, not switches. These work much like a loudspeaker sending out a tone and microphone picking it up but at a frequency too high for us to hear, and any movement inside the car disturbs the sound reflections and hence the level of signal picked up by the microphone half. If you could find the sensors you could just disconnect them, they may be inside the A pillar clip-on plastic, not sure. I doubt if there's a separate relay or fuse for this part of the alarm system as it's all low power electronics, it will be shared.

PS

There are P11 manuals for auction on Ebay UK on CDROM for a few pounds. A friend has just bought one for a 2001 Mondeo and it's the real deal (but not real if you see what I mean) and a mine of information.