viper 5704 shock sensor?

So I installed the viper 5704 on my car last week everything works great on it but the only thing is that whenever a loud truck goes by it chirps my car. Everything that I have read was that the 5704 had an external shock sensor (which came with the alarm but wasnt installed) The only two sensors I installed was the tilt sensor and a field disturbance sensor. So my question is how are loud trucks chirping the alarm without a shock sensor installed? When it rings on the remote is says shock sensor with a hammer icon.

Work out which is plugged into your shock sensor port or disconnect one at a time.