My Very First Check Engine Light (TM)

After about fifteen minutes of freeway driving this morning, I pulled off at my exit. As I was idling at a red light, I noticed my RPMs suddenly nudged upwards, and the light came on - for about three seconds. Light went out, RPMs went back down.

Hmm.

[SVXer95]

If your car is pre-96 you can pull the code and find out what it is. After pulling them, unplug the battery for a while to clear the codes. If the light comes back on and it is the same code, you will know where the problem lies

[Earthworm]

Have you ever changed O2 sensors? That would be my guess. (Wait for the code before changing of course)

It's a '95 ... and O2 sensors? Could be.

The light came on -- intermittently -- on the way home this afternoon. No drivability issues, of course ... it's just making me wonder.

(Through a coincidence, I have an appointment at my dealer in a couple days for something else. I'll mention it.)

Thanks!

[SilverSpear]

Ususally when the check engine light comes on, you should go check it out at a subaru dealer. this dealer has a special computer device which he hooks to a switch located behind the panel near the footrest of the driver. (below the fuse box) or on the other side also under the panel of the passenger side. he will read the problem's code and make the necessary service... that what I suggest you do.

[msvx95]

When I first bought my 95 svx, the check engine light came on only once after I went up a hill, but didn't see it come on again. I had an appt. with subaru to have them do some routine maintenance, etc. and I told them to run a diagnostic to tell me what the check engine light was for and it turned out to be both O2 sensors were bad.

[SilverSpear]

Originally posted by msvx95
When I first bought my 95 svx, the check engine light came on only once after I went up a hill, but didn't see it come on again. I had an appt. with subaru to have them do some routine maintenance, etc. and I told them to run a diagnostic to tell me what the check engine light was for and it turned out to be both O2 sensors were bad.

excuse me guys, but are the O2 sensors different than knock sensors??? it's just a mechanical language dilemma... because after I bought my car (after 5 months) my check engine lighted up, it was the first knock sensor. after 2 weeks again the same story, it was the second. I had them changed for $75 (both)including labor at subaru dealership...

Originally posted by SilverSpear


excuse me guys, but are the O2 sensors different than knock sensors??? it's just a mechanical language dilemma... because after I bought my car (after 5 months) my check engine lighted up, it was the first knock sensor. after 2 weeks again the same story, it was the second. I had them changed for $75 (both)including labor at subaru dealership...

They are different. Knock sensors are located on the engine block and sense "knocking", an internal engine problem caused when the fuel/air mixture ignites at less than the optimal time. O2 sensors, or oxygen sensors measure the amount of oxygen in the exhaust gas. Since both fuel and oxygen is burned in the engine, any oxygen that makes it past the engine would also indicate that unburned fuel has also made it past the egine....hence a fuel mixture that is too rich or a timing problem.



Dave

[SilverSpear]

Originally posted by red95svx



They are different. Knock sensors are located on the engine block and sense "knocking", an internal engine problem caused when the fuel/air mixture ignites at less than the optimal time. O2 sensors, or oxygen sensors measure the amount of oxygen in the exhaust gas. Since both fuel and oxygen is burned in the engine, any oxygen that makes it past the engine would also indicate that unburned fuel has also made it past the egine....hence a fuel mixture that is too rich or a timing problem.



Dave

thanks for the explanation, but I had them removed... 18 months ago.... do they affect greatly something in the engine???

[SilverSpear]

I have measured the emissons in my car at Bosch POS, they are gr8, no problems whatsoever... any comments ?