Yellow Check Engine Light

[e36surge]

Well gentlemen my M3 has been performing great even in the snow. I take her out every once in awhile when the temperature rises above -10 celcius.

However today as I was driving back from work at about 70 miles an hour when my yellow check engine light came on. I was running low on fuel so I filled up immediately at 94 octane as usual.

Would a low tank cause this? I have read a few posts here and some have encountered gas cap issues etc.

I will be going in to have the codes read and my next service is 20000 kms away as I just had the car serviced. 90K kms or roughly 60K miles on the clock.

Thoughts?

[johnnyBgood]

I would think so, being that the ECU senses & controls Air & fuel ratio's.....very sensitive,
did the CEL go out after you filled up?

johnny,

[e36surge]

No, as of this morning the CEL is still on. Car is running fine but I do hear my catalytic... hmmm O2 sensor....

Off to the stealership I go...

[paco1076]

Did you get this resolved? I know that the CEL will come on if you have "really" low fuel, but it should go back off within a few normal startups.

What did the stealership say?

[e36surge]

Sorry for the late update.

Well turns out the 02 sensor failed. Changed the sensor and the good 'ol stealership cleared the codes but guess what, the CEL came back on a few days later... I decided to try the good old 94 octane and what you know the light went off. Up here we don't have many 94 octane stations (prices up here are pretty high for go juice) so I had filled 91 a couple of times.

My fault I guess but the O2 sensor was the main culprit.

I don't get to drive her much when the white stuff is on the ground so she doesn't get filled often.

Just like women these cars...

[marlin hauser]

my check engine lights also were on,needing a smog I replaced the o2 sensor, unhooked the battery for ten min. to reset .My electric windows at the time were down and when i pluged the battery back on every thing is ok check engine light is off,but know my electric windows dont work? any ideas ?

[e36surge]

Have you checked all fuses and relays?