2002 subaru forester, can't get check engine light off

I have a 2002 Forester I have take it to 4 shops and each shop tells me something different. First 2 say to take it to the dealer and have them flash the computer. The dealer says that it is a faulty drain valve and the fourth states he has never heard of a drain valve. Hook up to a scanner and can not clear light. Unhooked battery for 30 minutes light was off for a minute but came back on. Getting extremely frustrated!

Do you mean purge valve?


Sheet dealer gave me stated faulty drain valve. Quoted me 400

Car runs great. Just can’t get it inspected with a check engine light on.

Disconnecting the battery won’t work. The ECM will detect the problem (whatever is causing this) as soon as you drive the car the first time, and turn the CEL back on.

I’ve never heard of a “drain valve” either. Sometimes vendors differ on their nomenclature. Maybe a drain valve for a Subaru is a purge valve for a Chevy.

This one does sound like you need a Subaru expert to help you. Either a dealership or an inde that specializes in Subaru.

Anyway, as far as for here on Car Talk forumes, best thing to do is post the DTC codes you are having. Have them read out for you and post them here. Folks here will respond w/some ideas I expect.

Oh, there is a “drain valve” I guess. At least on the 2002 Subaru Forester L F4-2.5L SOHC. It is part of the emission control system. Maybe look in the area of the charcoal canister or follow a line from the cannister, eventually should come to the drain valve. Not sure if this is the same as a purge valve or not. It’s probably only active when the ECM is testing the evap system. $400 parts and labor seems within reason to replace.

The code I am getting is PO447.

Take a look at this. It may be the valve is ok, but an electrical connector is the problem.


This is all I could find

The code states that the ECU has detected trouble with the valve circuit. It is possible that the valve itself may be causing the electrical connection problem but I would much more suspect a problem with a connector pin fault causing the trouble than the sensor itself. Higher than normal resistance of a connection will cause a voltage drop across the bad connection so the ECU doesn’t see the expected voltage range it looks for, so it generates the error code for a circuit fault rather than a sensor fault. You might be able to fix the trouble simply by disconnecting and reconnecting connections to the sensor. Don’t fall for the high dollar repair cost unless it is first proven that the sensor is really the cause of the trouble. If you get a factory service manual for the wiring it will show you where to find every connector and wire color for the circuit. Ebay is a good place to find manuals at a very reasonable price.

IF part is really bad, you could try and find the same used good part at a suby website or junkyard. U balk at paying 300 or more for new part yet have issue with using a good used part? Most all despise troubleshooting emissions issues and scream about buying new parts for a system that exists only to apsatisfy federal regulations to keep our air cleaner.

An evap valve is not that difficult to replace on a subie, I don’t think. I seem to remember that it sits near the canister on a braket. It also isn’t a very expensive port.
$400 are likely $stealer prices.