2003 Toyota Sienna (about 149,000 miles). The check engine light continues to re-appear, despite repairs. It's been very difficult to diagnose, at least for a regular repair shop.
7-18-15: First noticed that the Check Engine light was on (steady, not flashing). We took it to our small auto repair shop, which we have used for many years, but it is not a smog station.
7-21: The repair shop pulled trouble P0456 from the OBDII. I replaced the gas cap. The light eventually came back on.
8-27: P0450. We injected smoke into EVAP system and found a cracked section of hose. We replaced the EVAP hose near the gas tank. We removed a cover to get access to the gas tank. The check engine light eventually came back on.
9-17: EVAP trouble code again. We replaced the vacuum valve switch-vT (90910-12209). The light eventually came back on.
10-28: We cleaned and replaced O-ring in or near charcoal canister.
11-7: The light came back on.
At this point, we are thinking of taking it to a smog test and repair station, hoping they are better equipped and trained for this type of diagnosis and repair.
Do you have any suggestions? Thank you so much for your time and expertise!!
