I was out of the country for a month and when I got back I went to get my emissions test done. The car failed and the guy doing the test asked me if I had had repairs done to the car. I said no but that it was sitting for a month. He said that it needs to reset and after a week or so of driving I should be ok for a re-test. I checked with the Volvo dealer and they said that that was correct and that driving it should reset the modules etc. Today, a week later, I went in and failed again. He said the meter said it was either the cat converter, O2 sensor, or the battery. He suggested putting it in "drive mode" and drive it more. I asked what he meant by drive mode and he said Google it! I did and I don't see squat!

Does anyone know what he means? How can I get this car back to "normal" in order to pass my emissions test?

 

The car has to pass it's own "drive cycle". "Drive cycle" instructions are the fastest way to complete that self test. Drive cycle instructions are different for different brands of cars - so be sure to follow a Volvo drive cycle for your year model. However most normal driving will complete a drive cycle without having to follow a specific pattern. The exception would be cars that are consistently driven only short distances always too fast, or never at a constant speed (all mountain driving maybe) - there's a portion of a Volvo drive cycle that requires the car to be driven for a total of a least 18 minutes. (to test the Evap system)

Some scan tools have a function where you can watch the various areas get completed as you drive, and if you know what portion is not complete - you can skip to the instructions for that area rather than following the complete cycle. We would do that for our customers after an emission repair/failure - for they always waited to the last day to get their failing test. One way people screw up test completion is the gas tank is too full or too empty - the evap system won't test if too full or empty.

Was your battery weak or required a jump start when you returned? That can erase the "drive cycle information.

Here's a sample Volvo drive cycle - similar to the pattern I used to use - https://www.matthewsvolvosite.com/drive-cycle/

 

Thanks for all that insight. Yes, the battery was low, I guess, but it started the first day we were back and as a matter of fact we drove two hours to get our dog and two hours back. Some interstate highway, some rural roads. I've driven it close to home (no more highway driving) all week and I do have a heavy foot. It does still struggle to start but it does start. My mechanic ran diagnostics on it and said nothing was wrong (battery was at 12.7 and no codes) except something about the emissions codes were missing. He gave me some additional insight into the drive cycle - drive for 20-30 minutes at 40-50 mph, then park and idle with the AC off for 5 minutes, then rinse and repeat at least two more times. I'm going on another 2 hour road trip Saturday so maybe by Monday things will be corrected. In GA you have to have this emissions test by your birthday and mine's the 10th. Wish me luck!

PS, the gas tank is full, btw. Maybe that contributed to the fail.

 

We would complete Volvo drive cycles using the 85 access road between Clairmont and Shallowford road - would take about 1/2 hour, using a scan tool to watch as the sections were complete. Maximum of two round trips. (stopping and parking for x time when needed) And yes you need less than 80% in the tank or it won't run the evap test.

Does not need 30 minutes @45 mph, you need steady @ 1800-2200 rpms for the times quoted in the above link. Has to return to idle 6 or 7 times during the cycle. If you can't get the exact minutes in - they are cumulative. (2 minutes before you have to stop - adds to the next time you meet those parameters)