There is a difference with California legal and Federal legal emission requirements. However if the Hummer H2 you are planning on purchasing is equipped with all the Federal required emission components (which is originally equipped with) it can pass the California smog check and register with the CA DMV.
The rule is any USED vehicle (2008 or 2009 Hummer H2 qualifies as used) which is equipped with the necessary Federal Emission Components is eligible for California registration as long as the vehicle's exhaust emissions fall within California's limits and the vehicle's emission system has not been tampered with.
