Process Guide
What Actually Happens During a Mobile Emissions Test
A step-by-step look at the on-site process — from booking to a digital DriveON result — for anyone who has never had a mobile unit come to their yard before.
Updated: July 17, 2026
"Mobile emissions testing" is a simple phrase for a process with several official steps once you are standing at the truck. Here is what it looks like from booking through to a finished digital result, so a fleet manager knows what to expect before the unit shows up.
The Process, Step by Step
- Booking the visit. The fleet schedules a time and an eligible on-site location — for example a yard, warehouse dock, or jobsite — instead of booking a slot at a fixed test centre. Multiple vehicles can often be grouped into one visit when they are available and the site is suitable.
- On-site setup. An authorized mobile DriveON facility and registered DriveON technician arrive with approved equipment. The vehicle can remain at an eligible on-site location when safe access and suitable testing conditions are available. Ontario indicates that a test may be interrupted if it presents a risk to health or safety or may damage equipment, property or the vehicle.
- Vehicle identification and pre-test inspection. Before opacity readings, the technician performs a pre-test check. That typically includes confirming vehicle identification (such as VIN), checking for issues such as visible exhaust leaks, missing or improper caps, safety concerns, and — where OBD applies — access to the OBD connector. During the pre-test check, the technician confirms that the engine speed governor is not malfunctioning or visibly maladjusted.
- Opacity (snap-acceleration) test. Qualifying heavy-duty diesel vehicles receive an SAE J1667 snap-acceleration opacity test: with the engine at normal operating temperature, the throttle is opened from idle while approved equipment records the required readings and calculates the overall opacity result under the DriveON procedure.
- OBD system test where applicable. 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. OBD is not a universal replacement for opacity testing.
- Digital DriveON result. The result is submitted electronically. A fail report identifies the failed inspection component or recorded result, but further diagnosis may be required to determine the underlying cause. Problems should be evaluated and repaired before retesting; a same-day re-test is only possible if the issue can be corrected and the vehicle is still eligible to continue.
Logistics benefit, same inspection standard
Duty cycle and warm-up can affect how ready a vehicle is for testing, but the official procedure and pass/fail criteria are the same whether the inspection happens at a yard or a fixed VIC. Mobile testing is a logistics advantage — not a claim of a more representative or easier result. The engine must be at normal operating temperature as required by the procedure; a few minutes of run time does not automatically guarantee that.
What a Fleet Should Have Ready
- Vehicle registration / VIN information for each unit being tested
- Clear, safe access for the mobile facility and technician beside each vehicle
- Vehicles prepared so they can reach normal operating temperature before the procedure
- An on-site contact who can authorize next steps if a unit fails and needs repair before retesting
Getting the Result Afterward
Once a test is completed, the digital DriveON result is typically available for retrieval shortly after. Many fleets can look up a completed inspection using the vehicle's VIN, which matters when documentation is needed quickly for registration transactions. Related guides: how opacity and OBD testing apply and what happens during a mobile opacity test.
