- 11/13/2014
- 1 Min Read
- By: Alex Fiehl
How an OBD-II Scan Tool Can Help You Pass Inspection
An OBD-II scan-tool will help provide great insight into the dreaded “Check Engine Light” (CEL) and passing state emission inspections. Most states will not pass a car for emissions or safety inspection with an illuminated “CEL," so it's critical to have the right tools in your arsenal to get your car ready for a flawless PASS.
This gives us some options
Today’s cars are run by computers, meaning the computers monitor things like air volume and exhaust temperatures to adjust things like fuel mixture and spark timing to maximize emission-control, economy and safety. Cars sold in the US from 1996+ are required to have an “OBD2 connector,” which is basically a special connector that allows a technician to connect to the car’s computer for diagnostics.
Most OBD2 readers provide a basic ability to read trouble codes and erase them as well. Better readers will allow you the ability to check readiness monitors - but more on that later.
The OTC Pocketscan 3108N is small, affordable, and infinitely useful.
Read the trouble codes to then research online for possible sources of the problem. While there are general trouble code translations, we have found it more helpful to Google the code along with the car’s year, make, and model. The codes are generally "P-codes," like P0420. You will be surprised at how many people with your car have had the same issue, so use their experience to save you time and money! Even if you don’t do the work yourself, you are at least educated on the issue and can speak intelligently to your mechanic…. which is always good. Either it helps keeps them honest, or they have a buddy they can talk shop with. Win-win either way.
Clearing Codes
So emissions testing is due and you have a CEL, so you clear the codes outside the testing facility, fly through emissions with a “PASS” and then on down the road…. who cares that CEL comes on a mile down the road, right? Well, that won't exactly work.
Yeah, they thought of that - it's basically called the “drive cycle,” meaning the car must be driven under certain conditions to be sure the car is running properly. A complete drive cycle will need to be performed before the vehicle's readiness monitors allow the car to pass inspection - even if the CEL isn't illuminated.
Don't get an inspection unless they read "OK"
It's always worth the slight increase in cost to get a scanner that allows you to check the I/M monitors, sometimes called readiness monitors. "N/A" will indicate the vehicle is not fitted with that system, "inc" indicates the monitor hasn't finished its drive cycle yet, and "OK" indicates it's good to go. Don't go to an inspection unless they all read "OK," or you know your car is on an exemption list. Some 96-97 Volvo 850 models are on this list, as the monitors are known to take an exorbitant amount of time to go "OK." (Or they never do) I have seen a '97 Volvo 850 Non-Turbo pass New York State emissions inspection with all of the monitors set to "inc," as the vehicle is known to have this issue.
Emissions would not test because the car was not ready
My friend purchased a 2002 Volvo S60, and not soon after we had a CEL light. We scanned the code, wrote it down, then reset it. We then went online and searched the code and his car and decided a good first step was a minor tune up including replacing the air filter and checking most of the vacuum lines. The code remained off, but emissions would not test because the car was not “ready." They told us to drive the car and come back. After about a week of being turned away for the same reason we researched what a drive cycle is and found some very helpful information on Matthew's Volvo Site. You need to drive at certain engine speeds for a predetermined amount of time - this procedure varies among different vehicles. If you can find your vehicle's specified drive cycle to set the readiness monitors to "OK," you have a chance at passing emissions a lot quicker, and your scan tool will be able to tell you exactly when it's ready to to be re-tested.
We followed the directions, got an emissions test the next morning, and passed. Done!
