Shut down GSM-functionality

Module: Q2686H
Firmware: 660_09gg
OpenAT: 4.00 b04

When the module is registered in the gsm-network it is possible to de-register it with the cops=2 command. If no network is available this command does not work to stop searching for an provider. Even the wregc=3 command seems not to make any action. How can i shut down the gsm-functionality even if no network is available?