legacycentral bbs

My check engine light randomly comes on sometimes, both stopped and rolling. I think something might be loose, since the light goes out during moderate or greater acceleration. It seems to go out right about 3300 to 3500 RPM. Any ideas what the cause might be? Thanks.

There's no reason to guess what the cause might be. Pull the codes:

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

Thanks for the link. I've tried to pull the codes before, but I couldn't find all the plastic connectors. I'm not totally incompetent, it's just that the previous owner did some work and wrapped the wires in that area very tightly, hiding the connectors. I'm a little hesitant to start yanking on groups of wires.

Yeah, it can be hard to find them, but you really should. There are so many reasons that light comes on that it's impractical to try guessing them.

If you need to, you can actually just ground one or both of the relevant pins of the ECU instead of hooking the pairs of connectors together:

http://www.graphics.cornell.edu/~v/ecupins/

That might be easier since the connectors don't seem to reach each other. Thanks for an alternate approach.

Well to get to the bottom of this problem I had my mechanic check the codes using the official method, and there were none in memory!
This was no more than 24 hrs after the CEL last came on, and the battery was connected the whole time.
Haunted maybe?

"The official" method usually checks codes since the last time the car was started, right?

The connectors reach eachother, cut away some of the heat-shrink, or however the hell it's all tightened up under there, and check them that way.

I was told it would show all codes in memory that had come up, regardless of how many times the car was started. It also shows current codes that would be there since the last time the car was started. Maybe this isn't correct, I don't know.
The next time the light appears I will check using the connectors.

What's the "official" method?

As far as I know, both ways of reading codes from memory (with read mode and with a scan tool) read all the codes since they were last cleared.

I was referring to a scan tool as the official method.

what scan tool? Vikash's scan tool, select monitor, or some other third party tool?

I'd say unless it's a select monitor or vikash's scan tool.....I'd try the connectors.

I don't see why not just use them. That's what they're there for.