Sources reviewed October 9, 2026
The published schedule
CARB says most vehicles follow semiannual testing. Starting October 1, 2027, OBD-equipped vehicles move to four submissions per year; annual categories such as qualifying agricultural vehicles and California recreational/emergency-use motorhomes have separate treatment.
Where to look
CARB identifies Testing Details in the My Entity area of CTC-VIS as the place to see vehicle deadlines. Do not calculate a deadline solely from a website headline or assume another truck has the same date.
What to ask before renewing
Confirm whether the service price covers the required testing frequency, how retests are handled and what happens if a truck is disconnected. Ask how changes in vehicle assignment or ownership are reported.
For a fleet
Maintain one list with vehicle, responsible contact, due date and next action. Review exceptions separately so an unresolved truck is not hidden behind a fleet-wide summary.