In good old days we used to get a "sniffer" probe up our tail pipes. With the new Drive Clean program this method still applies for vehicles older than 1998, meaning they don't have an On Board Diagnostics (OBD-II) computer. For newer vehicles - no sniffer anymore. The test is being administered via vehicle's onboard computer.
MYTH: Disconnecting your battery will help your vehicle pass the Drive Clean test.
FACT: Disconnecting your battery will likely lead to an incomplete emissions.
The information in your vehicle’s computer may have been erased if any of the following happened recently:
• the vehicle was serviced and the battery was disconnected
• the battery was replaced
• the battery was drained, by leaving the headlights on, etc.
• the computer codes were cleared or reset to turn off the “check engine” light (if you had repairs done to your vehicle recently)
When either one of these happens your vehicle's monitors (sensors) go to sleep, and they won't wake up immediately after you re-connect battery power. So make sure to take your vehicle for a long drive to bring the sensors back online. However, for some vehicles this may take up to 2-3 days.
To ensure that your monitors have the best chance of becoming READY, especially after being reset, follow the following steps and information:
1. You must start this process with a fuel level of between ¼ and ¾ full. If there is too much or too little fuel, some of the onboard monitors may not run and will remain NOT READY. If your tank is below ¼, add enough fuel so that it becomes no more than ¾ full. If your tank is full, drive it normally until it is less than ¾ full (but more than ¼) and then continue with the steps below.
2. The vehicle must sit for a minimum 8 hour period, without a start.
3. Start the engine and before driving it, let it sit and idle to warm it up to normal operating temperature (this is normally when the car would be fully warm inside from the heater and/or the engine temperature gauge is reading “normal” or where it usually does after a long drive).
4. Drive the vehicle for a minimum of 10 minutes at highway speeds (between 90 km/hr and 110 km/hr).
5. Drive the vehicle for at least 20 minutes in stop and go traffic with at least four idle periods (engine running while at a stop).
6. Do not turn the engine off during the above driving cycle until the very end (no stopping for a coffee in between any step!).
7. It is not necessary to have your vehicle tested immediately after this drive cycle. Your vehicle will remain READY as long as the battery is not disconnected (or goes dead) or the Diagnostic Codes are cleared by a “scanner” of some kind. If you can’t make it in for a number of days, this is fine provided the Check Engine Light does not return.
In order for the vehicle to be deemed test "ready" it is only allowed to have 1 monitor "not ready". Except for vehicles made in 1999 and 1998 - 2 monitors.
Good luck!
