Ontario's DriveON program does not split heavy diesel emissions testing into a simple choice of OBD instead of opacity. A heavy-duty diesel emissions inspection includes a pre-test check and opacity test. Eligible vehicles also receive an OBD system check or OBD data collection according to model year and GVWR. Confirm both ratings on each unit before the visit.
Qualifying heavy-duty diesel commercial vehicles are subject to opacity testing using the SAE J1667 snap-acceleration procedure. OBD should not be described as a universal replacement for the opacity test.
A heavy-duty diesel emissions inspection includes a pre-test check and opacity test. Eligible 2007-and-newer vehicles with a GVWR of up to 6,350 kg also receive an OBD system test. Newer heavier units may also receive OBD data collection under the current DriveON directive.
Qualifying heavy-duty diesel vehicles are subject to opacity testing. A qualifying 2007-and-newer vehicle with a GVWR up to 6,350 kg also receives the applicable OBD system test, unless a listed exemption applies. That means some units receive opacity plus OBD on the same inspection — not OBD instead of opacity.
SAE J1667 is the standardized snap-acceleration (snap-idle) opacity test: with the engine at normal operating temperature and idling, the throttle is opened fully while approved light-extinction equipment records the required readings and calculates the overall opacity result under DriveON / O.Reg. 169/22. A pass means the vehicle is within its regulatory opacity limit at that time.
Where OBD applies, the registered DriveON technician connects to the vehicle's on-board diagnostics system and completes the OBD system test (or OBD data collection for newer heavier units where required). This checks diagnostic readiness and related emissions-system information according to the directive — it does not replace the opacity procedure for qualifying heavy diesels.
Registered Gross Weight (RGW) is the value on the vehicle permit and is used with the official DriveON triggers (for example ownership transfer or plate renewal on eligible heavy-duty diesel commercial motor vehicles over 4,500 kg RGW). Gross Vehicle Weight Rating (GVWR) is the manufacturer's rating and is used, with model year, to determine when an OBD system test is also required. Check both: RGW for whether an emissions inspection is due, GVWR and model year for which OBD components apply.
Ontario may list exemptions from the OBD system test in certain cases. If an exemption applies, confirm it against current ontario.ca guidance and the vehicle's documentation rather than assuming every unit in the 2007+ / ≤6,350 kg window will receive an OBD scan. Related guides: how mobile emissions testing works and what happens during a mobile opacity test. Schedule through Piotr Service.
