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Knock Sensor Bad?

I have a 200 Outback wagon. Over 90,000 miles. Never got to do the timing belt change yet. Now the Check Engine light is coming on. Error codes report a defective knock sensor. (not Adjusting) I never heard any knock yet. Engine is running fine, mileage is decent. Ive been using regular gas (not brand name) since I got the car. (Shell is a rare treat these days)

Anyone ever have to change theirs? Wher is it on the engine? Im imagining somewhere on the top of the block.

Im thinking of bringing it in to do the belt, change the sensor and while they are at it, change my lower coolant hose and thermostat that I couldn't change when I changed the upper hose. The sensor is around $300 so they say. Sounds a lot for a sound transducer (microphone?).....

Phil

Reply to
myamiphil
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Sounds par for the course. I've replaced a few. They're on the block toward the back on the left side.

Reply to
hyundaitech

Phil,

I had to replace the knock sensor on my '96 Outback 2.5L at about 60k miles. Check Eng lite code indicated the sensor but no other symptoms. The dealer charged me $43.05 plus tax in June, 2003, for Part #

22060AA031.

The sensor is located on the top left side behind the intake runners and is held down by one bolt that goes through the center of the sensor, which has a single wire coming from it.

EdP

Reply to
Ed P

I'm pretty sure the 'Knock' sensor you mention is actually a "NOx" sensor, which is part of the emissions control system. NOx stands for nitrogen oxides, which are a mix of greenhouse gases that contribute to ground level ozone, acid rain, smog, and can cause respiratory problems. For these reasons, our vehicles are subject to pretty strict emissions control standards for NOx and other tailpipe pollutants.

Reply to
JWC

There are also knock sensors which feed the engine controller. AT least in one generation, they were actually fed by microphones listening for knock, and adjusting fuel/air mix dynamically in response.

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Reply to
Todd H.

Found a web page that talks about this in more detail:

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Very cool stuff. :-)

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Reply to
Todd H.

Thanks guys.... THis time it is the knock sensor.... not the NOx sensor.... THe website sounds interesting. THe software too.... THanks....

Now I have to look into why I can't find a knock sensor online for the

2000 models..... and my dealer wants to charge a lot. PLenty of sensors for years before 2000. THe 98 models had a tech bulletin regarding changing the sensor and reprogramming the computer. I wonder if they fixed it in 2000? Hmmm....
Reply to
myamiphil

This is a guess, but perhaps aftermarket hasn't caught up for the

2000-2004 generation of engines. The 99 and prior models were quite different. You may be stuck having to get a Subaru part.

Best Regards,

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Reply to
Todd H.

Try looking here:

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Jeff

Reply to
jeff

I haven't followed all the links or read the thread carefully, but on some cars you can get spurious knock-sensor trouble codes. Did you try clearing it and seeing if it comes back?

Reply to
David

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