[VicVinegar]

Yeah I don't know how confident I'd be if it threw tranny codes at 250 miles. Something is wrong, or else it wouldn't have done it. Bad sensor, bad wiring to the sensor...something didn't work correctly, regardless if the transmission fluid is fine. Makes you question everything else.

 

[VicVinegar]

I am not going to discount your experience, but you should bear in mind that this is not necessarily everyone's experience.

CELs date back to...maybe 1980 or 1981, IIRC.
And yet, I have only had a CEL glowing on one occasion, and that was very briefly with my '02 Outback 3.0 VDC, as a result of the failure of the purge valve for the evaporative emissions system. I drove directly to my Subaru dealer, where they replaced the purge valve, cleared the code, and I drove off in about 30 minutes with no more CEL for the remaining 9 years that I owned the car.

My '81 Chevy Citation (one of the notorious X-cars) never lit up the CEL.
My '86 Taurus never lit up the CEL.
My '92 Accord never lit up the CEL.
My '97 Outback never lit up the CEL.
My '11 Outback has never lit up the CEL (so far!)

I have noticed that many people seem to think that it is normal for cars to have a CEL lit up for almost the entire time that they own their car, despite the fact that it is not normal.

In a similar fashion, many of the parents of my HS counselees would tell me that, "all HS kids have arrest records", despite the reality that in my neck of the woods, only about 5% of the students actually had arrest records. What they did not realize was that all of their child's friends might have had arrest records, but that was a reflection of the type of friends that their child cultivated, and not representative of the community at large.

For your own sake, please don't convince yourself that it is "normal" for cars to have the CEL lit up, because this is usually just not true for a well-maintained car.

I didn't have one in my '00 Honda until this year, when it came on after an oil change. The service writer cleared the code and it has never been back. Code was for an O2 sensor, which I could believe seeing the car has nearly 200k on it, but apparently its failure is not imminent. Either way, I don't see CELs as a "no big deal" kind of thing.