lhrocker Posted September 2, 2007 Share Posted September 2, 2007 Last Sunday, on the way home from NYC to NJ, my CEL light came on my 97 Legacy. I drove it home, shut the engine off, pull the battery cable for a couple of hours, then reconnected it. This used to work when I had "coil pack issues". When it restarted, the CEL was still on, so since I was going on vacation, I figured I would take a look at it when I got back. I got back yesterday and restarted the car, and the CEL was gone. I drove it all day today and everything seems fine. I used about 150 miles worth of gas when the light came on, so I thought that may be the issue. I also noticed that the idle was a little higher than normal (800 rather than 600). Since the light is gone, is there any reason to check for a code? I don't have a code reader and am not sure if an Autozone will check if the light isn't on. Maybe I should just forget about it for now? Quote Link to comment Share on other sites More sharing options...
nipper Posted September 2, 2007 Share Posted September 2, 2007 year and mileage please Quote Link to comment Share on other sites More sharing options...
lhrocker Posted September 2, 2007 Author Share Posted September 2, 2007 1997 Legacy L sedan auto with 130k. I bought the car with 119k, did a full tuneup with OEM parts, timing belts, water pump, exhaust pipe and such. No issues up till last weekends CEL. Now it's back to running good again. Quote Link to comment Share on other sites More sharing options...
nipper Posted September 2, 2007 Share Posted September 2, 2007 1997 Legacy L sedan auto with 130k. I bought the car with 119k, did a full tuneup with OEM parts, timing belts, water pump, exhaust pipe and such. No issues up till last weekends CEL. Now it's back to running good again. My money is on the front O2 sensor. The timing is right, and so are the symptons. It's getting old, and lazy in response. I usually do it at the same time i do a tune up after 100,000 miles. It will come back. May be a while, but it will. The code is gone now, so i am not going to recomend a pulling of the codes. nipper Quote Link to comment Share on other sites More sharing options...
lhrocker Posted September 2, 2007 Author Share Posted September 2, 2007 I was planning to have it done soon, so guess now is a good time as any. Should I go with OEM, or is anything fine? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted September 2, 2007 Share Posted September 2, 2007 Only OEM for the front o2 sensor. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted September 2, 2007 Share Posted September 2, 2007 I had a CEL that would come and go on my 93 leagacy, it was from the knock sensor. I'm not sure, but you may be able to use the "read memory" connector under the dash. Even if no code is present now, it will tell you if the code was triggered in the past. After replacing the knock sensor no more code. Quote Link to comment Share on other sites More sharing options...
nipper Posted September 2, 2007 Share Posted September 2, 2007 OBD II has no such thing. ALso the code woll reset itself if the puter finds no good reason for keeping the CEL on. You can try to read the code, but i doubt its there nipper Quote Link to comment Share on other sites More sharing options...
ferret Posted September 3, 2007 Share Posted September 3, 2007 The code should still be there, but now STORED. Some code readers and only read the current CEL ( when the Check Engine Light is ON ). After it goes off, it is then stored for up to 2000 cycles ( engine starts ) depending on the code and it's severity. Some codes are reported ( turns on the CEL ) immediately upon recognition. Others come on after 2 or 3 repeated failures. Then after a determined number of cycles WITHOUT the failure occurring again, the CEL is now turned off, and the code is now Stored instead of being active. Based on this, you have 'something' which is intermittent. Could be a sensor going bad, poor connector or something else. But I wouldn't throw any parts at it blindly without knowing what set the CEL. I would find some place or someone you know who has a tool that can read a 'stored' code. Quote Link to comment Share on other sites More sharing options...
nipper Posted September 3, 2007 Share Posted September 3, 2007 I have been here and done this. The code is not stored for a long time. the car cant tell if you replaced the faulty sensor or if its just intermittent. After a number of cycles it will erase the fault. nipper Quote Link to comment Share on other sites More sharing options...
Gloyale Posted September 4, 2007 Share Posted September 4, 2007 OBD II has no such thing. ALso the code woll reset itself if the puter finds no good reason for keeping the CEL on. You can try to read the code, but i doubt its there nipper I know OBD II Nissans still maintained a manual way of outputting codes, like was on there earlier style(in Nissan it's a screw on the side of ECU turned instead of connectors) I was not sure if Subaru had left that capability in there OBD II cars. Even so, the code is still stored. The CEL is turned off after a few cycles with no trouble. But the code stays stored for a long time, even after the CEL is off. That is why reading the historic(stored) codes is an excellent tool for diagnosing connection issues(since they are so intermitent) Once you read that code, by whatever means, you should have no problem fixing it. Quote Link to comment Share on other sites More sharing options...
nipper Posted September 4, 2007 Share Posted September 4, 2007 http://endwrench.com/images/pdfs/OBDIISumm04.pdf Its wiped out after 40 warm-up cycles, 80 if its a missfire (flashing CEL lamp). nipper Quote Link to comment Share on other sites More sharing options...
yohy Posted September 13, 2007 Share Posted September 13, 2007 Just had a similar situation with my '97 L, on again, off again, CEL. The car is my son's who is away at school. As it was intermittent and I was going to have the car over Labor Day, we let it go. Anyhow, he would tell me the car just didn't have the normal power when the light was on. Luckily, when I got the car the light was on, pulled the code and it was the knock sensor. Seems that when the light was on, the ECU was probably retarding the spark, so the car was a bit sluggish. Again, I would try to pull the code (if your anywhere near Portland, ME I would be happy to assist!), in my case it was easy enough. Quote Link to comment Share on other sites More sharing options...
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