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P0446 Fault on 1998 Lexus GS400: Causes, Repair Cost, and Vehicle Operability

Model: 1998 GS400 LEXUS Fault Code: P0446 Posted: 2009-11-18 14:42

Hi everyone, I recently purchased a used 1998 Lexus GS400 with 235,000 miles about a week ago. One day after refueling, the Malfunction Indicator Lamp (MIL) came on. I visited Advance Auto Parts, where they diagnosed code P0446 — EVAP Emission Control System Vent Circuit Malfunction. They reset the MIL, but it returned shortly afterward. Since then, I've driven the car for one week and it has been running smoothly without any noticeable performance issues. My questions are: - Is this fault serious or just a minor issue? - Will repairing it cost a significant amount of money? - Can the vehicle still run safely and reliably with this code present? I'm a student on a tight budget, so I really hope to avoid expensive repairs in the first week after buying the car. Sorry for any grammar or expression issues — I'm from France and English is not my first language.

Related fault codes
P0446
Comments (3)
Anonymous 2009-11-19 09:03

P0446 indicates a malfunction in the EVAP Emission Control System Vent Circuit. This could be due to a faulty vent valve or damaged wiring and/or connections. The repair is generally affordable, involving either replacement of the valve or fixing the circuit. The vehicle will still run normally despite this issue. The EVAP system helps reduce harmful emissions from vehicles. If you bought the car from a reputable dealership, they may cover the repair at no cost to you.

Anonymous 2009-11-21 07:23

I'm having trouble with my headlights turning on at night and suspect there might be a wiring connection issue somewhere. Not sure if this is related to the P0446 code, but it's worth noting for others experiencing similar electrical problems.

Anonymous 2009-11-21 14:34

The EVAP system fault (P0446) and your lighting issue are likely unrelated. It sounds like you're dealing with a common underhood diagnostic challenge — good luck with your repair efforts!