After a conviction for driving under the influence in California, you may have to install an ignition interlock device on your vehicle for a predetermined period. The IID requires that you blow an acceptable alcohol-free breath sample before your car is going to start.
Per the California Department of Motor Vehicles, once you have an IID installed in your vehicle, you need to uphold certain compliance requirements until your mandatory IID period ends.
What you must do with your IID
You need to have an approved installer place the IID in your vehicle and any other vehicles you plan to drive during your restriction period. You have to blow into the device each time you start your car, and you may, too, have to do so at other intervals, if the device requests that you do so. You also have to ensure that it undergoes regular calibration and inspection at least every 60 days to ensure it produces accurate readings.
What happens if you fail to comply
Failing to adhere to the rules associated with your IID may result in you having your license suspended or revoked. Common non-compliance issues include failing to have the device serviced or calibrated within the proper timeline. Tampering with the device, attempting to remove the device or having someone else blow into the device for you may also constitute non-compliance.
While an IID makes you submit a breath sample before driving, it typically also makes you provide breath samples during your journey to ensure you do not drink after getting the car to start.