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Asked: Apr 07, 2009 - 06:09 AM

Status: Closed

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carlat

2002 Lexus RX 300 check engine TRAC off and VAC light on, Codes P0440 0446 0441. Any ideas what this could be?

I have a 2002 Lexus RX300 Gas cap was left open after filling up had codes P0440 P0446 and P0441 removed but after driving about 350 miles lights (Check Engine, VAC and TRAC Off) came back on. The car is running ok, but gas mileage sucks, also seems that the pick up is not as good anymore.

In Maintenance & Repair > Electrical
In Makes & Models > Lexus > RX 300
1 answer - 230 days ago

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karjunkie

Date: Apr 07, 2009
Time: 11:07 AM

The DTC codes given are

1) P0446 : Evaporative Emission control system Vent control circuit
2) P0441 : Evaporative emission control system incorrect purge flow
3) P0440 : Evaporative emission control system

These codes indicate a problem with the EVAP system. I would first look for a disconnectted or damaged hose around the air filter box that goes to the evap solenoid, sometimes it gets knocked off when servicing the air filter. If the hoses are ok, the usual culprit when you get all three codes at the same time is the charcoal canister has failed. This usually results from constant overfilling of the gas tank. This will cause the 2 purge valves attached to the charcoal canister to fail. The other common culprit when all 3 codes come up is the vacuum switching valves. There are two VSVs. One is up at the air cleaner and the other one (the one that most frequently fails) is down underneath the car beside the gas tank, and adjacent to the charcoal canister. Presumably it fails because it is more exposed to road grime. One clue that it is a problematic VSV is that the above 3 codes appear at the same time. This problem does not affect vehicle driveability, although it might be a problem when you go for your emissions test.

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karjunkie

Date: Apr 07, 2009
Time: 11:07 AM

The DTC codes given are

1) P0446 : Evaporative Emission control system Vent control circuit
2) P0441 : Evaporative emission control system incorrect purge flow
3) P0440 : Evaporative emission control system

These codes indicate a problem with the EVAP system. I would first look for a disconnectted or damaged hose around the air filter box that goes to the evap solenoid, sometimes it gets knocked off when servicing the air filter. If the hoses are ok, the usual culprit when you get all three codes at the same time is the charcoal canister has failed. This usually results from constant overfilling of the gas tank. This will cause the 2 purge valves attached to the charcoal canister to fail. The other common culprit when all 3 codes come up is the vacuum switching valves. There are two VSVs. One is up at the air cleaner and the other one (the one that most frequently fails) is down underneath the car beside the gas tank, and adjacent to the charcoal canister. Presumably it fails because it is more exposed to road grime. One clue that it is a problematic VSV is that the above 3 codes appear at the same time. This problem does not affect vehicle driveability, although it might be a problem when you go for your emissions test.

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