You may request a registration extension from the California DMV. Visit a local DMV branch office. There is a $50.00 fee required to obtain a Temporary Operating Permit (TOP), unless you can show proof that your vehicle has been accepted into the CAP Repair Assistance Program.
All registration fees must be paid and your vehicle must be ensured in order to receive a temporary operating permit. The permit, when obtained for smog check failure reasons (must show proof of failed smog test), can be valid for 60 days from the date of the vehicle's registration expiration.