The environmental protection agency (EPA) and California smog check program considers any problem which causes the check engine light to turn on, a smog check failure. Your Dodge Caravan might be experiencing a problem which is only transmission related, however since the check engine light is ON, it will fail the smog check. It should be noted, that most often, transmission faults do increase emissions when causing incorrect shifting patterns or idle speed faults.
posted by SmogTips Support
