Clean Truck Check - Test Results FAQ
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OBD Testing
When performing the emissions compliance test, please ensure the test results appear in your CTC-VIS account prior to releasing the vehicle.
- If the test does not show up within 5 minutes after completing the test, you may need to re-test the vehicle.
- Common issues
- Unplug all other devices connected to the diagnostic port to ensure they don’t cause communication interferences
- Verify the communication between the vehicle and the OBD test device
- Ensure the internet connection is stable
- If the results still do not appear after multiple attempts during the emissions compliance testing, contact hdim@arb.ca.gov
OBD Results
Awaiting CARB's Response
We recommend contacting the test device vendor to verify if there are any issues on their end that might have prevented the test from being transmitted and processed in CTC-VIS. If the vendor identifies a potential issue with the submission from our end, please have them reach out to their assigned device certification engineer at CARB for further assistance.
Not Ready
A vehicle is not ready (and cannot pass an emissions compliance test) if it has not been operated enough since the OBD memory was last cleared (also known as a “code clear”) and thus has not had sufficient time to complete a full diagnostic assessment to determine if an emissions related issue exists.
A code clear can occur if a fault has recently been repaired, or if a vehicle recently has had a dead, disconnected, or replaced battery. The current minimum operation threshold for a Clean Truck Check emissions test submission is for the vehicle to have at least five (5) Warm-Up Cycles (WUCs) since “codes cleared”. A warm-up cycle means driving a vehicle so that the engine coolant temperature rises by at least 40 degrees Fahrenheit after the engine is started and reaches at least 140 degrees Fahrenheit for diesel engines (160 degrees for alternative fuel engines).
Do NOT schedule a Clean Truck Check OBD emissions test if codes were recently cleared. Drive the vehicle normally to make sure your vehicle has operated sufficiently to be able to complete the test. For example, 5 warm-up cycles can typically be obtained within a week of driving. For more information, please visit OBD Readiness Criteria.
Test Results Could Not Be Determined
Please unplug other devices connected to the diagnostic port, verify the communication between the vehicle and the OBD test device, and ensure the internet connection is stable. If you receive the same results after multiple attempts, the Clean Truck Check Referee, operated by CARBTest.org, can assist vehicles with a condition that makes a typical inspection difficult due to design, malfunctioning condition, or inspection incompatibility. Please provide your Vehicle Identification Number (VIN). CARBTest.org will provide information regarding the next steps required
Fail
Please obtain any needed repairs and retest the vehicle. Please note that repairs could result in codes being cleared, and your vehicle might be “Not Ready” (and cannot pass an emissions compliance test) if it has not had enough operation since “code cleared”. However, Clean Truck Check requires you to submit a passing emissions compliance test before the vehicle(s) deadline.
A code clear can occur if a fault has recently been repaired, or if a vehicle recently has had a dead, disconnected, or replaced battery. The current minimum operation threshold for a Clean Truck Check emissions test submission is for the vehicle to have at least five (5) Warm-Up Cycles (WUCs) since “codes cleared”. A warm-up cycle means driving a vehicle so that the engine coolant temperature rises by at least 40 degrees Fahrenheit after the engine is started and reaches at least 140 degrees Fahrenheit for diesel engines (160 degrees for alternative fuel engines).
Do NOT schedule a Clean Truck Check OBD test if codes were recently cleared. Drive the vehicle normally to make sure your vehicle has operated sufficiently to be able to complete the test. For example, 5 warm-up cycles can typically be obtained within a week of driving. For more information, please visit OBD Readiness Criteria.
Testing Results Not Showing
Test results will only show within 90 days of the day the vehicle was added into CTC-VIS.
- For OBD test submissions:
- OBD results take 0-1 days to populate
- If you do not see your OBD results in that timeframe, please contact your OBD device manufacturer and ask to resend the files to CARB.
- CTC-VIS only shows OBD compliance emissions tests submitted on or after October 1, 2024.
- For OBD test submissions to CARB prior to October 1, 2024, CTC-VIS will not show the submitted test results. Please check with your tester for the submitted test result information.
- For non-OBD test submissions:
- Please check the test submission for VIN typos and ask your customer to check their vehicle account for VIN typos.
- If the vehicle account has a VIN typo, they need to deactivate the VIN and add a new vehicle with the correct VIN.
- Please check the test submission for VIN typos and ask your customer to check their vehicle account for VIN typos.
All heavy-duty vehicles need to have proof that the engine meets appropriate emissions standards by having the manufacturer ECL properly affixed on the engine and fully legible. If you are unable to obtain the ECL, you must request the manufacturer write you a letter stating the label is unavailable. Engine information must be provided on the manufacturer's letter. A copy of the letter must be kept in the cab of the vehicle in a place known to the driver.