[ArleneW]

Hi, I have a 2000 Subaru Outback. I had it repaired about a month ago because it had been accelerating very poorly, hesitating, and misfiring. Then one day it just stopped and would not start again. The mechanic I had it towed to put in new spark plugs, timing belt, and water pump. He also put sealant in the radiator and did an oil change. The check engine light had been on. The mechanic who fixed it said that the CEL had to do with the spark plugs. Got it home and it is working great, but then the CEL came on again (before I even got it home). I had it checked at same mechanic and at AutoZone. Codes p0325 (knock sensor 1 circuit malfunction) and p0420 (catalyst efficiency below normal) came up. My inspection is due in April. The guy at Autozone sold me a fuel system additive and told me to use premium gas for a week and then come back. The mechanic told me it will probably need a new catalytic converter, but might not need a new knock sensor. I’ve been trying to research it online, but I’m not really a “car person”. A friend said he thought there are tricks to get it to pass inspection involving fuel additives and driving like 100 miles. He even gave me written instructions. Are you familiar with this? I don’t know what to do. I’m living on half my usual income paying back loans from clients and friends for the previous repairs, and for the new front brakes I had done in the fall (pads, rotors, and driver’s side caliper). Can you give me any insight or ideas on what to do? Please let me know.

 

[eagleeye]

replacing the knock sensor may fix the p0420 also.

the P0420 is a mild code. gets turned on by many things, the LAST thing to do is to swap a perfectly good expensive cat converter for another.

how many miles on this car?

why did the mechanic change the water pump? (did that come with a timing belt kit?).

what kind of sealant did he put in the radiator?

 

[plain OM]

The mechanic told me it will probably need a new catalytic converter, but might not need a new knock sensor.

Not sure why the mechanic said that.

P0325 is likely due to a faulty knock sensor or faulty wiring between the sensor and the engine control module. The attached guide suggests what to check to narrow it down. A knock sensor for that car, if it's confirmed bad, is far less expensive than a converter.

 

[ArleneW]

Thank you for your responses. The car has about 228,000 miles on it. I do not know what kind of sealer was used. On the receipt, it is listed as sealer bls, if that helps. I also do not know why he replaced the water pump. I do know that the mechanic I purchased the car from (a different one) told me that replacing the timing belt and water pump is routine maintenance and suggested I do it since he wasn’t aware when it was done last. I had been trying to put that money together without borrowing it since I purchased the car last year. But I hadn’t told this mechanic that.

 

[ArleneW]

I also knew the knock sensor would be much less expensive than a new catalytic converter. I did not know that it could trigger a P0420 code. Perhaps that is why the only suggested part in the printout I received from the scan they did at AutoZone was the knock sensor. Perhaps I should follow the advice the guy at Autozone gave me?

 

[eagleeye]

hopefully it is just the regular 4.4oz subaru coolant conditioner,...and not a typical sealer.

did anyone say the exhaust was open at the front up by the cat, or the cat was physically rusted or damaged?

______


and I was looking at your location: good news,

the cops can't write you a ticket until May 1st, when the april 2018 punch holed sticker expires. (so between now and May 1st, they will just remind you to get it done).

bad news. the cops like to stand in the road on nice quiet days in springtime looking.

 

[AWDFTW]

Also, you can get knock sensor on Ebay for cheap. Takes like 10 minutes to install.

 

[ArleneW]

No one said anything about the cat until now, not during the previous repairs. And even now it was just because of the CEL code.

I was looking on eBay and on amazon and saw knock sensors listed for my car from $10 to $115. Why the big price differences? Are the cheaper ones ok to use? I know the mechanic who did the last repair doesn’t want you bringing your own parts, but I think the one who did my brakes wouldn’t mind. He changed a headlight bulb for me when they couldn’t figure out how to do it at AutoZone.

Yes, I know that about the cops in my area. I’ve often gone through those traffic stops. And the better the weather gets, the more you see them. ?

Thank you. All of you are really helping me. I was pretty worried.

 

[AWDFTW]

I've been running a $10 ebay knock sensor in a friend's 2000 Legacy for about 2 years now.

 

[ArleneW]

Thank you, that is great to hear.

 

[AWDFTW]

Also, I could replace the cheap ones off Ebay easily 5 times before a name brand one cost. Presuming they last at least a year I'd still be ahead.