O2 Sensor = Check Engine Light

[AlcyoneDaze]

Seems like I just come on here to post problems... lol

Anyway, I bought the car from the previous owner with the Check Engine Light on. The code is #28, for the passenger side oxygen sensor, which he replaced (both sides) along with the catalytic convertors (both sides), but the light would not go out. The local Subaru dealership told him it was a bad ground to the PCM, which according to the reciepts, was fixed. The CEL remained on, at which point Subaru said it was the Powertrain Control Module simply recieving the code in error. Still with me?

Well, I didnt completely believe him, so I re-replaced the O2 sensor and the code is still there, even after clearing it using the method described in the how-to. The CEL remains on. I would just assume live with it, but it will be a hard thing to explain when I go to sell my car - so, my question; IS there a possibility there is just a fault in the PCM causing this? A new one isn't cheap, and I just want to know all the possible causes. Thanks!

[JaySVX]

We're here to help solve your problems, after all, it IS a community, not just a few guys with the same car.

Why would you sell your car? CEL adds character! Like my brake light that won't go out, things that no longer work and we can't quite get to fix are re-defined as features!

Subaru said it was a bad ground, and that they fixed it. I would re-check that ground, and everything around it before the PCM. If all else fails, perhaps someone can provide you with the replacement parts that happens to have spares lying around.

[AlcyoneDaze]

Haha, I love the sense of community that comes with owning an SVX - this site makes owning one a joy instead of a scary headache... Before owning this car I'd never even changed my oil, now I'm able to do complicated stuff with my eyes shut (last week I had a dream about vacuum hose routing... for real)!

Anyway, the CEL was only intermittent before taking off my intake manifold, now its constant anytime I get over 45mph and lift off the throttle. Where are the grounds for the PCM/O2? Pics or diagrams would be helpful. Should I just clean them with solvent/alcohol and re-attach?

[JaySVX]

I have a relatively complete list of service manuals at http://www.serial.cc/ that your welcome to. It has wiring diagrams that should be able to help you in finding what you need.

[AlcyoneDaze]

pardon me, but I have no idea where to even start looking in that list...

maybe some pics of the engine bay and where the grounds for the PCM are?

[AlcyoneDaze]

found the ground, cleaned it, and the CEL is GONE for the count!!!

thanks for the help Jay, that red light was annoying the hell outta me for the past eight months

[subru92svx]

You might want to put some dielectric grease on that ground. It helps make a better connection and prevents corrosion. I always use it on all my connections and I put it on every battery terminal I touch. Just thought I might mention it.

[Bizarre]

Hey, I have the same issue. Tell me how to find that ground!

Adrian