96 Legacy wagon troubles

Hi all. Just purchased my first Subaru. She's a 96 2.2 automatic wagon. I purchased this car for a gas saver because I have a full size truck and I blew up my Audi. Anyway, the inspection is due by the end of November and I have a few issues to clear up. I have cleared the check engine light, and within about 25 miles, the car is showing me 3 codes, 2 are pending and the other is already logged. P0325 knock sensor 1 circuit (bank one or single sensor). I looked at the sensor and can see a small hair line crack on the sensor. Would replacement clear this up? The other 2 codes are O2 sensor heater circuit (bank 1 sensor 2) and Manifold absolute pressure/barometric pressure circuit range/performance. I was just at the junk yard and picked up an alternator for the car, so I grabbed a MAP sensor while I was there and replaced it. I have read that the small filter in the vacuum line can become clogged near the MAP sensor, but I am able to blow through it with no problem, even though all of the foam from the out side of it is gone.

 

Wondering which O2 sensor it is, the one in front of the cat or the one behind it? Also, will simply replacing the sensor fix my problem, or is something else causing the sensor code to come up? Also, is there a way to clean these sensors?

 

As far as the MAP sensor goes, I checked all of the vacuum lines and they all look OK, anything else to look for?

 

Thanks in advance for any help! Hoping to get this thing through inspection on time unlike any of my previous vehicles.

 

BTW I purchased this car for $700 so I do expect to have some problems.

More than likely the knock sensor will prolly fix that code. I heard the knock sensors are prone to failure although i have never come across this, but having a hairline crack.... thats a good place to start..

 

O2 heater code, you say B1S2, that would be downstream sensor just past the cat. There is a heater element inside the sensor that heats it up so it can read faster, and it went out. SUPER common... and not just with Subaru's.

 

as far as MAP sensor issues, you could try a different one, but being a mechanic, without looking at ecm data through a scanner, as long as you have good vacuum to that sensor, try another one.

Thanks a lot for the reply. I know a lot of times people get codes for a sensor and it's really a good sensor just something else is giving it a bad reading. I just found out that this car also has what you guys refer to on here as torque bind. Wish I could have driven it more before I bought it. AWD fuse did nothing so I guess that means parts need to be changed in the transmission.

More than likely the knock sensor will prolly fix that code. I heard the knock sensors are prone to failure although i have never come across this, but having a hairline crack.... thats a good place to start..

 

O2 heater code, you say B1S2, that would be downstream sensor just past the cat. There is a heater element inside the sensor that heats it up so it can read faster, and it went out. SUPER common... and not just with Subaru's.

 

as far as MAP sensor issues, you could try a different one, but being a mechanic, without looking at ecm data through a scanner, as long as you have good vacuum to that sensor, try another one.

 

http://i364.photobucket.com/albums/oo88/gtmci84s/20140914_170328.jpg

 

 

I checked to see if there was vacuum to the MAP sensor and there is not. What is the part located directly to the the right of it in the picture? There is vacuum to that on the line on the far right of it, but not to either of the other lines. Could this part be bad? Should there be vacuum to the MAP sensor all the time? Thanks!

 

In regards to my last post, the FWD light came on after sitting all day with the fuse in.

Ok, THAT is a vacuum switching valve. It does just that, controls the flow of vacuum. One side runs to the pressure sensor next to it, the other side runs and measures pressure near the charcoal canister. An easy way to diagnose that valve, on the connector there is two wires, one 12 volt, other is ground signal supplied my ecm. Simply start car to get vacuum to the valve, unhook vacuum line to pressure sensor NEXT to it, backprobe the GROUND signal wire and make it ground, it SHOULD click and you get vacuum..... they are simple two wire valves that get power and ground, thats all they need to work. If powering it with 12 volts gets nothing, then its bad. If it works...... thats another issue....

OK, so I didn't have long enough pieces of wire to test it while it's hooked up but I took it off and put power to it. I tried hooking it up both ways and can hear a very quiet ticking noise when putting power to it but I can not blow through it. I assume this means it's bad?

Ticking means it COULD be working, but without checking the "operation" then its only guessing. Unhook one of the long vacuum lines from the car as a tester piece. Or find help.

I've seen the vacuum solenoid for the MAP sensor fail more than the MAP sensor itself. In fact I've never had a MAP sensor fail on a Subaru. I'd test the solenoid but I'm sure that's the issue for that cel.

The o2 code being a circuit malfunction replace the o2 sensor. Same with the knock sensor.

Concerning the tq bind placing a fuse in the FWD fuse holder in the engine bay is ONLY for transmission diagnosis and not for everyday driving. You'll actually do more damage with a fuse installed. How does the trans fluid look? I've came across tq bind in many customer Subarus and if it's not really bad a good thing to try is get all of the old fluid out and put the correct Subaru trans fluid in. Then drive until it's up to temp and while in a parking lot do tight figure 8's. Do that for for about 5 mins. Now I can't say it's going to fix it for sure but I have had good success over the years doing this method and actually heard of this fix from my friend who is a Subaru Master Tech.

Thanks for the info. My O2 sensor code has not come back sense I replaced my alternator and cleared the codes. I replaced knock sensor yesterday. Is there a good place to order a vacuum control valve online? If not, I will probably just go get a junk yard one.

 

I only planned to leave the fwd fuse in for a week or so until I get to changing transmission fluid. It's clean but I noticed yesterday that it is way over full on the dipstick. Over the full hot mark when it is cold... Also seems strange to me that it had to be driven a few times with the fuse in before it actually kicked in to FWD could this indicate anything? Also, my trans light does not flash at start up, this means there is no trans damage right?

The Trans Temp light only flashes when there are trans codes stored in the computer.

I would test the valve by apply a power and ground supply while blowing into one of the vacuum lines off the valve. It should be closed or blocked with no power and open flow with power.

If the battery charging system wasn't supplying 12+volts while running is possible that the sensor wasn't heating up and working right because of low voltage.

Yeah and if the solenoid is bad just get a used on because they are probably expensive at the Subaru dealer.

The Trans Temp light only flashes when there are trans codes stored in the computer.

I would test the valve by apply a power and ground supply while blowing into one of the vacuum lines off the valve. It should be closed or blocked with no power and open flow with power.

If the battery charging system wasn't supplying 12+volts while running is possible that the sensor wasn't heating up and working right because of low voltage.

 

Thanks. I tried this with the valve already and I was unable to blow through it when it had power to it. Maybe I will be able to grab one at the junk yard today.

 

About the O2 sensor, that's what I thought but now after driving it for a few days the code is pending again.

 

Knock sensor code gone after replacement.

 

Thanks all for the replies!

I finally got around to getting a vacuum solenoid from the junk yard. I got it home and tested it. Same as the old one. If I put juice to it, it should allow air to pass through the line that goes to the MAP sensor, right? It lets air through the other connector either way but power or no power, does not let air pass though the MAP sensor line. Both the old and the new used one are this way.