I get the Following ECU Codes 28, 34 and 37?
 

I checked them all out, they are:
28: Knock Sensor #2 Left side
34: EGR solenoid or Circuit
37: Oxygen sensor#2 Left side

Where should I begin:
Can't seam to find the Knock sensor #2 without taking off intake manifold.
O2 sensor should be easy,
and the EGR is medium difficulty.

1)Any suggestions?
2)Anybody know a common problem that could effect all 3, or even 28 and 37, I have had code 34 for a long time.
3) A really easy fix?

The car has failed our AirCare test, (Smog test) so I expect several of these are the culprit:
I'll be checking for the results page and post what failed shortly.

Chris,


Rufus (Mike Wirt) has a really easy method for changing the knock sensors. They can be changed from the front without removal of the manifold. Here is what he said:

"Remove the belt cover, the alternator/power steering belt and the a/c belt. Remove the alternator from the car.

Now here's the trick:
Remove the engine lift bracket, with the compressor still attached, and move it off to the side. Do not disconnect the hoses. There is enough flex in the system to move the whole assembly well out of the way. I was able to carefully wedge it against one of the radiator supports, but a bungee set-up would probably be safer. If you pulled the battery, the whole thing would probably rest right in that spot nicely.

Now you have lots of room to work, and the "rear" knock sensor actually becomes the easiest one to do. Finding the connector is still a little tricky, but you can put your whole hand in and grab the wire to wiggle it around while watching from the outside.

The whole job took me about an hour and a half, much of which was spent cleaning a mouse nest out from under my intake manifold.

I hope this helps someone out in the future. My car runs smoother now than I ever remember, so I think the knock sensor must have been failing long before it ever starting throwing a code."



The left O2 sensor is very easily accessible once you get your car on a lift. You can buy the OEM ones or get replacements from http://www.oxygensensors.com

Off hand I don't know of any one specific problem that could throw all three codes.

When was the last time the spark plugs were changed? How is it running?

.

Thx John.
I have not changed the plugs yet, so at least 30kMiles.
I'm going to try and locate the test proceedures for the Knock sensor, and probably try to diagnose the EGR stuff, the O2's were replaced a little while ago and it could be a bad wire.

Chris,

Sometimes a small exhaust leak will cause the O2 sensor to throw a code. The exhaust system around the sensor should be pretty tight. The probable leak area would be around the flange where the two exhaust pipes go into the main cat.

That happened on my 96. I went through a few sensors on both sides before I found the problem.

if you really want to test the knock sensor you need a timing light a hammer and a rod... i wouldnt bother i would just replace it... they go bad on subarus.. and subarus are not knowen for throwing ghost codes... oh wait there is a certain resistance value that the knock sensors have but i cant remember it off hand... but it can still read that value and be bad...

svxcess: Thx John, I'll look for a leak, but I'm pretty sure the 96 has 3 O2 sensors instead of 2 and a leak would probablt be heard but I will check anyways.
Suby Fan: Makes sense just to replace it, but I want to make sure there is nothing as simple as a loose connector first. I too have a rats nest of leaves in under the intake manifold and over time have been attempting to clean it out, that may be why I suspect a loose wire.

In the process of cleaning out the area and looking around I left th H6-3.3 cover under the hook to the side and crushed it by closing the hood. DOH:eek:
Thx for the help, I'll be checking out the costs of these little parts shortly.
I may decide to pull the manifold anyways to get under and replace as many hoses and parts as I can.

be very, very careful when pulling the manifold. There are many small hoses under there which may have become brittle from heat over 15 years and break.

Check this thread by mbtoloczko, along with the excellent .pdf (with photos) on how to do this:

http://www.subaru-svx.net/forum/show...manifold+hoses


This would also be an excellent time to change the infamous PCV valve.

.

Since the errors are on one side of the engine check that your timing belt hasn't jumped and that your coils/plugs are not misfiring.

Timing Belt:eek: I never thought of that. Oh boy, that could explain it, but the car runs fine, and get the same mileage???
I think I'm just gonna take it to Subaru, let them give me an estimate.
If I can't get it to pass aircare I have to spend $600 trying, and they will give me a conditional pass.

I was just poking arouynd again today to see if I could find the left side Knock sensor, and the wire for it goes under another area under the manifold???:confused:


I also attempted to clear the codes and reset everything so I could figure out if any of these are intermintent codes.
Well, I either could NOT clear them or they are all perminent failures.
1) if I screwed up and didn't clear the codes right, then the cars for sale.:cool:
I checked the codes first, 37,34,28, yup, they are still there.
I turned it off, plugged connectors into both 1 and 2, started car, turned car off, checked codes, and they are all still there. I tried to clear them again, same process, codesstill there.
Anybody see anything wrong here? or is it plausable that these codes are solid errors?

2) if indeed these are all bad parts, I need to replace the left O2 sensor, Left Knock sensor and who knows what for the EGR code 34, any suggestions?

3) I plan to pull the manifold so I can replace the PCV and all the hoses, and suck out the rats nest while replacing the Knock sensor, and perhaps some other EGR circuit type parts, theres one in there but I suspect an electrical connection.

204,000 miles, and still runs.

Anybody have a picture of the left knock sensor with the manifold off?

do you want a picture of what it looks like or where its located? because if you know what it looks like once you remove the manifold its pretty eazy to spot if you know what your looking for

I found a picture of it in http://www.subaru-svx.net/photos/fil...czko/30310.jpg mbtoloczko's locker. I saw the same pic somewhere isle, but I see it now.


Now I'm trying to figure out what part to replace for code 34?

OK, I've done a few checks, poked around to see if I can find a missing vacuum line or whatever, no luck. (code 34: EGR Solenoid of circuit)
Tested the resistance on the left Knock sensor(code 28) spec says close to 560k ohms, it read 570k ohms, and checked the right to compare, it read 552k ohms, so looks to be ok. I disconnected as many connectors as I could find, and plugged them all back in..I hope:eek: .

I'm realizing that my body is too old to lean over the hood any longer than 20 minutes or so without a beer in my hand, so I may decide to let the suby dealer take my money.

Before I do that I'm disconnecting the battery to see if that will reset my ECU and see if its really posting perminent codes. And see what Beav says about my emmision report, the SVX has been spoiling me with impecable reliability, so it was about time for some $$$. FYI, the car still runs 110%, its just not passing aircare, so I'm not allowed to drive it till I fix it or spend $600. I jhave til June 26th to get either one of these done:eek:

OK, I just hooked the battery back up, started up the car, started about the same as it always does. warmed it up, took it for a spirited ride around a few blocks, stopped at a garage sale, didn't buy anything, but was almost tempted to buy the fluorescent Black light thing for $10, no idea why, glad I didn't.

Got the car home, checked for codes, nothing, no solid codes.
will take it out for a drive today, see if it passes aircare, whats another $24CDN, $16Euro's?

wish me luck!

Problems like that aren't going to fix themselves. Expect the codes to return.