Battery Backed Sounder

When the CJB arms the active anti - theft system, in either the perimeter mode or the volumetric mode, it sends an arming signal to the battery backed sounder on the LIN bus. When the system is armed in the volumetric mode, the CJB also sends an arming signal to the tilt sensor (if fitted).

On receipt of the arming signals, the battery backed sounder and the tilt sensor respond with status signals. If the CJB does not receive the status signals within 12 seconds, it assumes there is a fault and responds with a disarm signal to the battery backed sounder and/or the tilt sensor and stores a related fault code. If the battery backed sounder is disarmed when the active anti - theft system is armed and the system is subsequently triggered, the CJB instructs the AJB to energize the horn relay and use the vehicle horns to sound the audio warning in place of the battery backed sounder.

When the battery backed sounder is armed, the CJB sends a periodic (heartbeat) signal to the battery backed sounder, which prompts the battery backed sounder to monitor the vehicle battery supply and the LIN bus link with the CJB. The sounder will operate if:

• It receives an alarm signal from the CJB or the tilt sensor
• The power supply or the LIN bus link from the CJB is disrupted.

The tilt sensor measures the longitudinal and lateral angle of the vehicle over a range of ±16° from the horizontal. When the active anti - theft system is armed in the volumetric mode, the tilt sensor stores the current vehicle angles in its memory and monitors the tilt sensor readings. If the vehicle angle changes in either direction by more than the alarm limit, the tilt sensor activates the battery backed sounder.

If the alarm system is active and the battery or battery backed sounder is disconnected, the battery backed sounder will operate, but there will be no visual warning.