Here's how you can enable or disable System Services in Location Services on iOS 6.
1. Open the Settings app.
2. Tap on Privacy.
3. Tap on Location Services.
4. Scroll down and tap on System Services.
5. You'll see a list of options, toggle the switch of each to the On or Off position.
6. Here's a list of System Services options:
Cell Network Search
Diagnostics & Usage
Genius for Apps
Setting Time Zone