Q: The check engine, Trac off and Vsc light came on my car. The code that came up is P0446 (Evap System Vent Control Fault).

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I drive 2001 toyota sienna with 100,000 miles on it. The light came on after three weeks of purchasing my car. I got the code by getting it scanned by a shop. The codes have not gone away, it's been 3 months now. I tried tightening the gas cap, it didn't work. I also tried putting 93 octane gas, it didn't work. After one week of trying these steps, the lights went away for 3 days in between and came back on after the 3 days. Now it has been about 2 months since the lights have remained on.

My car has 110000 miles.
My car has an automatic transmission.

Hi there. That light is not going away until the fault has been properly diagnosed. The code may or may not be the same. The code that is stored is a guide for a qualified technician to use. It does not offer a diagnosis, only a guide to the system with the fault. The code you mentioned, PP0446, is an evaporative emissions code when the system detects a fault during self testing. This system prevents the escape/release of fuel vapor into the atmosphere as regulated by our lawmakers. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a check engine light inspection.

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