Check engine light, WHY is it not on?

[loonibab325i]

I know.. i shouldn't be complaining, but it has me asking myself questions.

I would think the check engine light would come on because 1, I don't have my oxygen sensor plugged into my exhaust, and 2, it didn't even come on when I took it out completely.

Does the check engine light not come on if your oxygen sensor isn't plugged in correctly or what? I'm not getting anything! I'm starting to think that the engine light wont come on, but you would think the car would go into a safe mode, or not run properly without it engaged, no?

-Abe.

[smonkbmw]

to the best of my knowledge, depending on the wiring, it doesnt work at all on a swap car. i could be wrong.

[hoveringuy]

Unfortunately, mine works.

I've replaced the O2 sensor, checked the wiring and power to the heater circuit (it's Ok) but still get a flash of the "check engine" light if I'm idling for more than a minute or so at a stoplight. Not always, but sometimes.

It turns off 10 seconds after I pull away.

BTW, I connected the heater circuit of the one I pulled out and that friggin thing gets HOT!

[z31maniac]

My check engine light goes on and off, seemingly at random.

The car is running good, but slightly rich, so I don't worry about it.

[matt]

It doesn't work if you don't hook it up.

[loonibab325i]

It doesn't work if you don't hook it up.

elaborate, please?

[Van Westervelt]

Does it come on when you turn the ignition to on before you start it? If not, recheck your wiring. It should work if you did it right.

[James Crivellone]

to the best of my knowledge, depending on the wiring, it doesnt work at all on a swap car. i could be wrong.

I've wired it on every 24V swap car i've done....works fine

[matt]

There is a small gray wire in the M50 X20 connector. If you connect this to your check engine light, your check engine light will work.

[etxxz]

*edit: huh nm i just ran through my wiring exel file and found out that i must have missed something. should have been e30 c101 pin 12 "DME check engine" (in most e30) and s52 is X20 pin 8. thanks!

[loonibab325i]

I am using a pre-made wiring adapter though, AKG one. Isn't that covered by that?

-Abe.

[matt]

I am using a pre-made wiring adapter though, AKG one. Isn't that covered by that?

-Abe.

Should be, unless AKG did it wrong. Key on, engine off... have a CEL?

[Van Westervelt]

Should be, unless AKG did it wrong. Key on, engine off... have a CEL?

He still hasnt even confirmed this. lol

Could also be as simple as the bulb itself on the back of the cluster is bad. But first you need to see if it EVER comes on. Stop being a lazy pita.

[etxxz]

Should be, unless AKG did it wrong. Key on, engine off... have a CEL?

i did, so were a few other lights but they all went off after ignition ex the abs light (abs didnt quite work)...i wasn't running after-cat o2 sensors (obdII) for a while, then i added O2 sensor simulators and no change. what are your thoughts?

[loonibab325i]

He still hasnt even confirmed this. lol
Could also be as simple as the bulb itself on the back of the cluster is bad. But first you need to see if it EVER comes on. Stop being a lazy pita.

I can't confirm anything when I don't have my car with me. It's at the shop getting the clutch re-installed. I sent it to them when i had the motor out, I wish I would have just done it my self, now that I have looked into it, I can't believe I had sent it to them, but they offered to get it fixed for no extra charge, so i'm not going through the hastle of dropping the tranny, etc etc.

Thanks for all the advice guys, and I will let you all know what's up with the CEL once I get my car back.

-Abe.