The maintenance light and VSC light turned on during my commute. P0440 was the code I read when I plugged in my scan tool.

I started by looking at the hoses connecting the vapor canister to the gas tank and did not see any issues there. Taking out the canister for testing was pretty straightforward, but a few of the hoses were really stuck on there. Once the 5 hoses and the connector to the VSV are taken off, there are only 4 screws holding it in place. On the bench, I was able to check the functionality of the VSV for EVAP using a 9V battery. The valve functioned properly, and air did not escape per the service manual, so that was not the culprit. Next up was the canister itself. There was no obvious damage to the outside, so it was time to check the air flow.

In the service manual, sections EC-9 and 10 were needed to fully debug the issue. While the EVAP port was functioning properly, I was not able to get the purge port to hold a 1.01 inHg of vacuum when the air inlet port was closed. With all of the other tests passing and this one failing, I was pretty confident that I found the root cause. To be safe, I went through the remaining tests, which has you check the VSV for pressure switching valve, and VSV for canister closed valve - both of which functioned correctly.

I went back and forth on getting a used or a new canister since they are fairly expensive, but decided on going new just for the piece of mind. The new canister comes with a new set of hoses, new VSV for EVAP, and even a new connector and harness for the VSV. Once I received the part, I went ahead and checked the purge port for pressure, and it held without issue!

The EVAP readiness test passed after running the drive cycle, and I was able to pass smog later that week.

My 2001 Toyota 4Runner engine light came on with the VSC light. It really baffled the heck out of me for over 2 months. Especially when the vehicle had to be inspected in August. The stealer ship wanted to look at it and told me they didn't no how long it would take to figure it out. I am sure they would take hours on it. I decided not to get robbed, so I went to Auto zone to get a code. I don't remember the code but it had something to do with the VSC switch or the Charcoal Canister. I went to the stealer ship to get the switch. I had no choice to buy OEM because I know Toyota vehicles will give U hell if it not OEM. I payed $80 bucks. I changed the VSC switch located under the spare tire. The engine light and VSC light stayed off for almost 500 miles and appeared again. I then took the vehicle to a friend who had a shop. He did a smoke test. The O-Ring on the charcoal canister was leaking due to dry rot. The O-Ring cost $2. bucks he only charged me $100 to change. It is now 3000 miles later light still off. I want to warn people not to buy a whole charcoal canister as they are very pricey. When I had this problem I noticed a lot of posts with the same vehicle problem. I believe Toyota is very aware of this problem with there crappy charcoal canisters.