Service Manual / Knock Sensor

[Dano58]

What is the best service manual for my son's '99 Impreza RS2.5? We
need to fix a couple of things, and I checked our library last night
but they don't have the Chilton's for this car. Are there any on-line
resources?

The immediate focus is figuring out where the knock sensor is. We have
a CEL and the code indicates an issue with that. Based on some on-line
research, tightening or loosening the knock sensor may fix the code.
But I don't know where the sensor is or what it looks like!

Thx,

Dan D
'99 Impreza RS2.5 (son's)
Central NJ USA

 

[Bob Bailin]

What is the best service manual for my son's '99 Impreza RS2.5? We
need to fix a couple of things, and I checked our library last night
but they don't have the Chilton's for this car. Are there any on-line
resources?

The immediate focus is figuring out where the knock sensor is. We have
a CEL and the code indicates an issue with that. Based on some on-line
research, tightening or loosening the knock sensor may fix the code.
But I don't know where the sensor is or what it looks like!

Thx,

Dan D
'99 Impreza RS2.5 (son's)
Central NJ USA

One more thing:

Amazingly, there's absolutely no mention of the location or how to
replace the knock sensor in the official 95 Subaru Impreza service
manual or supplements.

 

[Bob Bailin]

What is the best service manual for my son's '99 Impreza RS2.5? We
need to fix a couple of things, and I checked our library last night
but they don't have the Chilton's for this car. Are there any on-line
resources?

The immediate focus is figuring out where the knock sensor is. We have
a CEL and the code indicates an issue with that. Based on some on-line
research, tightening or loosening the knock sensor may fix the code.
But I don't know where the sensor is or what it looks like!

Thx,

Dan D
'99 Impreza RS2.5 (son's)
Central NJ USA

Generally when a code for the knock sensor shows up, you should replace
the sensor. Get it from Subaru, not aftermarket. It's not very expensive.

The knock sensor looks like a 1" dia. steel "O" with an electrical connector
on one side. A 10mm-head bolt goes thru the center of the "O" and attaches
it to the block.

If your 99 impreza is similar to my 95, then the knock sensor is located
on the driver's side of the engine, if you look down between the arms of
the intake manifold on the back end. Use a flashlight and you'll see a round
thing with a bolt going down thru it and a wire coming off the back side.
The bolt will be tight, but shouldn't require more than 20-25 ft-lbs torque
to remove. If it seems stuck, get someone with an impact wrench to
loosen it, don't break off the bolt head, and use a 6-point socket with an
extension to get at it. Disconnect the wire after removing it.

Bob

 

[Dano58]

One more thing:

Amazingly, there's absolutely no mention of the location or how to
replace the knock sensor in the official 95 Subaru Impreza service
manual or supplements.

Thanks, Bob, I appreciate the response.... Interesting that it's not
in the manual!

Dan D
'99 Impreza RS2.5 (son's)
Central NJ USA

 

[Dano58]

Generally when a code for the knock sensor shows up, you should replace
the sensor. Get it from Subaru, not aftermarket. It's not very expensive.

The knock sensor looks like a 1" dia. steel "O" with an electrical connector
on one side. A 10mm-head bolt goes thru the center of the "O" and attaches
it to the block.

If your 99 impreza is similar to my 95, then the knock sensor is located
on the driver's side of the engine, if you look down between the arms of
the intake manifold on the back end. Use a flashlight and you'll see a round
thing with a bolt going down thru it and a wire coming off the back side.
The bolt will be tight, but shouldn't require more than 20-25 ft-lbs torque
to remove. If it seems stuck, get someone with an impact wrench to
loosen it, don't break off the bolt head, and use a 6-point socket with an
extension to get at it. Disconnect the wire after removing it.

Bob

Bob, is this it?

http://i24.photobucket.com/albums/c30/ddibiase/Subaru/P8270008.jpg

http://i24.photobucket.com/albums/c30/ddibiase/Subaru/P8270010.jpg

Thx,

Dan D
'99 Impreza RS2.5 (son's)
Central NJ USA

 

[Bob Bailin]

Bob, is this it?

http://i24.photobucket.com/albums/c30/ddibiase/Subaru/P8270008.jpg

http://i24.photobucket.com/albums/c30/ddibiase/Subaru/P8270010.jpg

Thx,

Dan D
'99 Impreza RS2.5 (son's)
Central NJ USA

Yup, that's it!

 

[Dano58]

Yup, that's it!

I found a little more info on some other sites. Going to try and pic
up the part today and replace it tomorrow, hopefully that will fix the
P0325, and then we can work on the P0446!!

Dan D
'99 Impreza RS2.5 (son's)
Central NJ USA

 

[GJ]

Dan,
Did replacing it fix the problem. There are lot's of interesting
email threads here and it is nice to know if they have a happy ending.

Geoff

 

[StephenW]

The rule of thumb at our shop, if it's a knock sensor code, its a knock
sensor.



--
Steve
ASE Master Tech
L1 Diag
Currently residing at a Subaru Shop
4.5 years doing tires and alighnments

 

[Tony Hwang]

The rule of thumb at our shop, if it's a knock sensor code, its a knock
sensor.

Yup,
I replaced one on 2000 Impreza RS according to the DTC. cost ~20.00 from
eBay.