We do recommend having your PT Cruiser's oil changed before the smog check. Contaminated oils are high in Hydrocarbons (HC) and may present a rich mixture to the engine chambers, via blow-back gases which are returned to the intake manifold. Your PT Cruiser's PCV (positive crank ventilation) system is designed to allow your engine to breath fumes located in oil compartments (oil pan, ect.). The fumes are then burned through the combustion process. If the oil in your engine is old and contaminated due to inadequate oil changes it may cause your vehicle to fail the inspection.
Your PT Cruiser will not fail the smog check because the Change Oil Light is on, but it may fail if the HC levels within the oil are high.
