1998 Subaru Legacy P0325 & P1443

I have 1998 Subaru Legacy (2.2L) with 217,000 miles. The check engine light has been coming on and off for the last week. I finally bought a scanner and got these codes (when light was off):

P0325: Knock Sensor Circuit Malfunction
P1443: EVAP Control System Vent Control Function Problem

First, are these related? In other words, does one cause the other?

I just been to the dealer twice in the last 4 months and have spent over $4k on other problems (cat converter, brakes, timing belt, etc), so I really am trying to keep costs to a minimum. The car isn't worth much more than this.

For the P1443 code, I'm thinking I might try getting an OEM fuel cap since the CEL light has come on immediately after re-fueling. I have tightened it and it seems to have some effect sometimes.

For the P0325 code, should I replace the knock sensor?

Thanks.

I know subarus CAN go 300,000+, but cmon, dont you think an evaperative canister is prob. worn out by now, The knock senser thing I know you can simulate, I think your engine has seen its day but Im no expert, I used to have a repair shop about 15 yrs ago and cause cars are so tech. now I had to give it up, but still all my reletives and the nieghbors still bring there car problems and they keep me entertained, The basics should be checked, I once had my uncles car and it had boo-coo codes set, it was the battery! checked base voltage with engine off was 5.5 volts, but still had enough cranking amps to start the moter, and no one caught it! The days of the backyard mechanic are over for us but you can still check the basics and get lucky somtimes, I hope a sub. tech comes on here, good luck

I'm hoping I can get another 20k-30k miles out of it. My kids are just starting to drive and I want them to wreck this car rather than a new one.

I know I can measure the resistance on this sensor, but I don't know what it's supposed to be. Also, why do you think I need to replace the evap canister?

well, the computer is telling you that there is a malfunction in the evap. canister area, I can speculate all nite long, but my experience with them(ev.can.) is by the time you got that many miles on somthing, due to refilling the tank and accidently over-filling by attendants or intentualy packing as some people do, the result is premature detereration of the internal carbon-particle pack inside., The granular carbon particles start to migrate into the purge solinoid, thus the distorted electrical values, causing lite. As I have no more problems to work on here, I will go further and explain one basic princible;If you know how somthing works, you can fix it, supposedly. modern cars(yours is considered modern) are designed to keep emissions at minimum AND tell the owner when there is a problem. It could also be related to the knock-sen. code theoreticly you have a rich mixture because the purge solinoid is stuck open from particles and cant close, its only supposed to be open for the first twenty min. of driving, to purge the fumes that it has assorbed from the tank, chew on that, let somone else try to help, I hope this helps,but you can just put a piece of tape over the code lite and get by, but I recomend you follow it through, and dont give up.possible reasons for knock sensor;The mech. that worked on it last forgot to plug it back in.the sensors wires are melted,shorting out,defective shorted sensor.If your sucking strait gas fumes straigt thru an EMPTY canister,and the purge valve is stuck open.,then the comp is trying to compensate for a vacum/and or rich fume,savvy?

Not right away. Check the wiring & resistance on the sensor. See this article for more details:
http://www.obd-codes.com/p0325

Don't just replace parts without a proper diagnosis!

A friend of mine with a 99 Subaru had a P0325 a couple years back. The car was under warranty so he took it to the dealer. They replaced the sensor and he was good to go.

OK, I'm a little new to OBD codes. Which one of these codes would cause the CEL to come on? Would either one by itself cause the CEL to come on or is it because there are two codes?

Thanks for your input.

Follow-up: I brought the car a mechanic and he replaced the knock sensor. He said the original one was out of spec. Since it's been replaced, the car has been fine. No CEL and the car has more power. The P1443 code has never returned.