So I just bought a 90 subaru legacy LS and the "check engine" light is on. The guy I bought it from told me what the problem was so replaced the faulty part and the light is still on - even after disconnecting the battery for 30 min... So I was wondering how do you check the trouble codes on this car? Do I need a special code reader deal or is there a blinking light to count or what?

Next to the ECU there is 2 connectors. a set of green ones with 1 one only and a set of black ones with 1 wire only. Plug the black ones together, turn the ignition key to on without starting and the CEL light on your dash should flash to give a code.

 

Read this here

http://www.surrealmirage.com/subaru/engine.html

If there were past problems that were fixed and the ecu was not reset will the trouble codes still be present?

I read that they do, and I think they also keep the affect that they do (sometimes it goes into a kind of safemode.) But now I am having the issue where the CEL light goes on and off but the code is always there, even if the light is off. So I'm not sure how much of the info out there is correct.

Heres The codes!

12 - starter switch

22 - knock sensor

35 - canister purge soliniod valve

 

I have a spare car to rob parts off of (well, until the insurance company hauls it off - I totaled it last monday!) so I changed the starter hoping to get rid of code #12 - starter switch - but it didnt!... What about the rest of the codes? I just bought the car and it had a head gasket blow and a shop replaced both of the head gaskets and the timming belt abouit 3000 miles ago (before I bought it)---- If I swap out the knock sensor will it eliminate code #22? What about the canister purge solenoid valve- code# 35? Where are these items located and is it a simple replacement of parts issue? What do you all think? I hope so, since I have the parts and all!

I'm pretty sure you need to reset your ecu (take the positive battery terminal off for 3mins or so) to clear the codes..

 

The purge solenoid can either be taken out and replaced with 60 odd Ohm's resistor or you can swap in another one. It sits on top of the motor and has a vacuum pipe from the TB going to the charcol canister.

 

When I got my EJ22 running in my Brat it had codes 22 24 and 35. After fixing code 35 and clearing the ECU code 22 went away as well and has not come back. Still working on that stupid code 24....

 

I hope that helped a bit.. So go out there and disconnect the power for a bit then come back with the new codes.. Oh, you will also want to take the car for a drive to warm it up as some problems only come up when the car is warm.