This Photo Tech article addresses an emissions canister/EVAP vent-system performance problem that set a code P0446 on a Buick Rainier. It is not the first time the problem has occurred on the vehicle. It was fixed about a year ago by cleaning the vent solenoid. This repair for resetting of the code led to more extreme measures. You may not agree with the repair method, but the customer was not going to replace the canister, the vent solenoid and other components or buy the updated filter that gets mounted higher above the transaxle. In fact, possibly the only way to cure this problem would be to mount the filter on the inside of the vehicle’s body someplace. It was either a case of doing what is shown in this Photo Tech or driving the vehicle with the “check engine” light on. Nothing else was really going to happen.

With the code cleared and everything reassembled, the vehicle was put back into service and has been running now for a few months with no real recurring problems. Will the problem come back? Probably, since the customer hasn’t moved and continues to drive on the roads causing the dust and the dirt that was initially present. The moral to the story is that although it would have been nice to replace everything on the vehicle, it would not have cured the problem. The problem would have come back in a reasonable period of time. What’s the real solution? Move or buy a different vehicle. Other than that, service on a somewhat regular basis is about the only solution to the problem.

A special thanks goes out to students Shannon Carl and Marcus Sitko at the University of Central Missouri Automotive Technology Management Department and their instructor, Dr. Alexander Richards, Associate Professor, for the use of their facility for shooting the photos in this issue of Photo Tech.