1992 Subaru Legacy ECU Codes

[mikeamondo]

I've got two Legacys... a '90 and a '92. I ran the check sequence as described in the Sticky Note section on this forum and found the following codes:

 

With the Black Connectors:

 

1992: 12 (Cam Angle), 31 (Throttle), 32 (Oxygen), 35 (Canister Purge Solenoid Valve)

 

1990: 32 (Oxygen)

 

With the Green Connectors, while driving:

 

1992: 35 only

 

1990: No fault (steady blinking)

 

Soooooo.,..... If I understand how this works.... with the black connectors, you're seeing ANYTHING that has sent an error code while driving in the recent past, and with the Green Connectors, you are seeing those things that are sending an error code NOW. Correct? And if so, does that mean the only thing I need to worry about is the Canister Purge Solenoid Valve on the '92?

 

And.... what the hell is a Canister Purge Solenoid Valve, and how big of a pain is it to change?

 

By the way, both cars run okay, but the '92 is weak on steeper hills. Other than that, and the check engine light being on, you would not know there was a problem.

 

On the '90 model, showing no errors on the green connectors, there is some hesitation here and there.... almost like a slightly clogged fuel filter, but the filter is new.....

 

Any help on this, as always, is greatly appreciated!

--Mike

[Legacy777]

You are absolutely correct in your understanding of the codes and the diagnostic connectors.

 

The canister purge solenoid is part of the evaporative emissions system. The ECU tells it to open at certain times so that intake manifold vacuum draws the gasoline vapors out of the charcoal canister in the front of the engine (black round thing).

 

The purge solenoid is located under the passenger side intake manifold and isn't too bad to get to.

 

These pics should help

http://www.main.experiencetherave.com:8080/subaru/images/injectors/

 

Second row down you'll see a pic of the the solenoid valve.

[mikeamondo]

Thanks for the reply and the info! So... does this purge valve thing do something really important, or is it just so the car can be sold in California? Would it's failure result in the low power on the hills we've seen? What I'm getting at here is.... is it really worth it to fix it when the cars running okay?

 

Thanks,

Mike

[ra_der]

Thanks for the reply and the info! So... does this purge valve thing do something really important, or is it just so the car can be sold in California? Would it's failure result in the low power on the hills we've seen? What I'm getting at here is.... is it really worth it to fix it when the cars running okay?

 

Thanks,

Mike

 

All the purge valve does is suck out the vapors from the gas tank that have collected in the charcoal cannister, It won't affect performance at all.

However your check engine light will stay on until it is fixed. I just bought one for $80 and change. Easy to change out.

[Legacy777]

The issue you can have is if the valve fails open, you can get have a poor idle situation.

 

It's easy to change, I'd recommend just to change it. If you don't want to spend the money, post in the marketplace and find a used one.

[ra_der]

The ECU will only tell the valve to open when the car is in motion.

What the check engine light is really saying is that it has detected an open circuit when it signaled the valve to open, usually the fine wires in the solenoid have broken.

If the valve is stuck open, possibly from debris from the cannister, the ECU won't know it.

We've run across this code about three times in the last half dozen years, always a failed solenoid that just keeps the CEL on and will fail your emissions test.