How the Test is Done
The Ontario Drive Clean emissions test can only be performed at an accredited Drive Clean facility by a certified emissions inspector.
Pretest check
Before performing the tail-pipe emissions test, the inspector will do a visual check. If the inspector finds any of the following issues, it must be corrected before the emissions test can continue, as it could lead to injury and/or the test equipment may not work properly:
- missing catalytic converter(s) and/or gas cap(s)
- defects in the fuel filler pipe
- visible smoke coming from the tailpipe
- any problems the inspector believes would prevent the vehicle from being tested safely
If the Malfunction Indicator Light (MIL), also known as the "check engine" light, on the dashboard remains illuminated in 1998 and newer model year vehicles, inspectors will advise the owner that it may indicate an emissions-system malfunction.
Emissions test
Ontario's Drive Clean program uses an Accelerated Simulation Mode (ASM) emissions test as its primary test method. This test is conducted on a dynamometer, a kind of treadmill that simulates actual driving conditions. The inspector inserts a probe, which is connected to a computer, into the tailpipe. The probe measures the tailpipe emission concentrations of nitrogen oxides (NOx), hydrocarbons (HC) and carbon monoxide (CO). The vehicle emissions are also measured when the vehicle is at idle, in what is called a “curb idle” test. The idle portion of the test measures HC and CO.
Some vehicles, such as those with full-time all-wheel drive, cannot be tested on a dynamometer. These vehicles are given a two-speed idle test, where emissions of CO and HC are measured at "curb idle" and 2,500 revolutions per minute (RPM).
The Drive Clean system then compares the test results to the emissions standards for the vehicle make and model year, and the inspector presents them to the vehicle owner in the form of a pass or fail report.
