Driving with an expired smog check can lead to legal and financial consequences. In California, for instance, driving with an expired smog check can result in a fine of up to $1,000, depending on the severity of the violation. Additionally, the DMV may refuse to renew your vehicle registration until you pass a smog check. It is essential to comply with smog check regulations and renew your vehicle's registration on time to avoid penalties. For smog check in Rancho Cucamonga, you can visit a licensed smog check station.