OBD vs opacity testing for Clean Truck Check

OBD test (2013 and newer engines)

For OBD-equipped heavy-duty engines, the test is a data submission: the tester connects an approved device, pulls the emissions-related OBD data, and uploads it to CTC-VIS. Active emissions-related fault codes or an illuminated MIL will fail the vehicle, so clear and verify repairs before submitting.

Opacity test with visual inspection (OVI)

Pre-OBD engines and vehicles without usable OBD get a snap-idle opacity test run to the SAE J1667 procedure, paired with a visual inspection of the emissions control equipment. Opacity limits are tighter for newer engine families than for older ones, and a missing or tampered aftertreatment component fails the visual portion regardless of the opacity reading.

What a compliant test record needs

• Credentialed tester name and credential number
• Test date inside the vehicle's 90-day compliance window
• Device name/serial used for the test
• Pass or fail result, with photos supporting the inspection
• Submission to CTC-VIS — an unsubmitted pass does not make the truck compliant

Failed tests and retests

A failed vehicle stays out of compliance until it is repaired and passes a retest that is reported before the deadline. Keeping the failed test, the repair invoice, and the passing retest together is what makes an enforcement conversation short.

Logging tests in CTC Tracker

The log-test flow pre-fills the correct method for each vehicle, requires every CARB-essential field before it will save, stores up to four photos per test, updates the vehicle's compliance status, and can turn the test straight into an invoice for the customer. See how the deadline schedule interacts with test dates.