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31 March 2010 @ 11:36 am
Auto Motives Update II  
The manual mentions that the light might come on if you're low on fuel, as small amounts of air can get into the fuel line and cause a misfire. Sounds like trying to start the engine with a nonfunctioning fuel pump would cause the same effect—though it's odd that it would hit 50 miles later.

Based on the manual and the Very Useful Feedback I've been getting from the Hive Mind, I'm gonna open the gas cap and re-seal it, then go check the tire pressure*, and see where that leaves me. EVERYTHING, including the manual, suggests that a) It's Nothing Urgent Or Critical and b) It May Just Go Away By Itself In A Few Days, esp. if I do those little things.

(If the light were blinking, of if it were the SERVICE light instead of "Service Engine Soon", that would be another matter.)

Consensus: If it's still shining merrily on Monday, then I'll worry.

Thanks to everyone for all the information and advice!

*My usual service station doesn't have an air hose, so I've been uncharacteristically remiss in keeping tabs on my tire pressure. Yes, this may have contributed to the blowout.
Bobyourbob on March 31st, 2010 07:30 pm (UTC)
Mine was on for almost two weeks recently. It magically went out two days after getting a fresh 3/4 of a tank of gas. It doesn't like the 10% ethanol they pump in to make the plus cheaper than regular.
Araquan Skytraceraraquan on March 31st, 2010 09:18 pm (UTC)
Indeed, sometimes the cause of the light can Just Go Away... the system is basically rigged as a low pass filter given the fact that an automotive environment is nothing if not rich in fluctuations in the data stream. So even after the problem is fixed it can take several trips before the computer decides it's fixed enough to turn the light off. Of course, only your friendly local OBD II reader can say for sure. Definitely give it a look if it's still on after a while.

Mine's been on for over a year. I have an OBD II reader though, and know exactly what the problem is- primary oxygen sensor heater failure. Which means the O2 sensor that's upstream of the catalytic converter (there's also one downstream- the secondary) which needs to reach operating temperature to sense optimally won't do so as quickly- it's heated by the exhaust stream anyway but that can take several minutes.

My car has around 110K miles on it as well, and I'm told that O2 sensors will tend to start failing around then. I have a replacement for it now, but in spite of the fact that the primary sensor is in a trivially easy place to get to on my car, actually getting it out has proved less trivial. I may have to break down (no pun intended) and take it to a mechanic.
Your Obedient Serpentathelind on March 31st, 2010 09:57 pm (UTC)
I live in California. If my O2 sensor is having issues, I'll fail my smog test, so I can't just let it slide.

Edited at 2010-03-31 10:03 pm (UTC)
Araquan Skytraceraraquan on March 31st, 2010 10:33 pm (UTC)
Yup. But I don't, so I can.

It's mostly been sloth and money that's kept me from having it looked at professionally. Probably more of the former, though if the thing does strip threads on the way out, I'll be on the hook for a new catalytic converter, and therein lies the money problem.

Of course, you can still let it go a few days... unless your car is getting smogged this week...
Richardf8richardf8 on March 31st, 2010 11:17 pm (UTC)
Get the code read. Most common cause is that the fuel system won't hold a vacuum. If that's the case, generally its not a worry, but in CA you may not pass an emissions test if the light is on. Service by itself, usually with a wrench graphic is high tail it to a mechanic.
Pyatpyat on April 1st, 2010 02:25 am (UTC)
The light in the Haunted Police Car was on for literally months and months. The guys at the autoshop would turn it off anytime I brought it in for an oil change. Then... it went off when I lost my gas cap and bought a new one.