Today while I was driving on the 101 on my way home this indicator light turned on. I referred to the manual and it states that this has to do with emissions and such. I just spoke with my brother who used my car last night and he was nice enough to fill up my gas tank. The only thing is that he filled it up with "89 octane fuel", instead of Premium / 91 octane fuel. He only put a gallon or two in there. A buddy of mine suggested that I just purchase an octane boost and that should even out the fuel, but I don't know. I've driven the car for about 40 miles since this happened last night. Please, please, I need some suggestions please, I hope it's something I shouldn't really have to worry about.

Here is a picture of the indicator light that came on.

 

The lower octane will not cause the MIL to come on and will not hurt the motor if only a couple of gallons. Check to see if your brother tightened the cap ( 3 clicks). This would be the most likely cause.

 

I already checked that, the manual states to check that first. It says to check the cap and then take three driving trips...so I did. I drove around for like ten minutes, turning the car off everytime. So I gave it a few minutes and then turned the cae back on a drove for a few minutes and so on. The light is still there. It was really, really hot today (105) could that be a factor here? It's now about 75 outside though and the light is still on. I am going for another short drive to see if the lights is gone. Wish me luck. Thanks.

 

In my experience the 3 trip rule doesn't always work. As long as your S is running good, I would still bet the on the gas cap cause. Try filling up the tank again. This will pressurize the system quicker. If that doesn;t cure it you'll have to pull the OBD II code for a cause.

 

I'm sorry but I am a bit of a novice at this so could you please explain what you mean by "OBD II" code? Thanks.

Well I tried the cap again and just drove around for about 15 minutes and it's still there. So what else can I try? What makes me think it's not the gas tank cap is because when I unscrewed the cap I heard the tank get depressurized. So who knows????

 

What about dropping some octane booster even some 101 octane trick fuel?

 

any more suggestions...can i be driving the car around like this? or could it be something more serious than just a fule cap?

 

Your octane is not the cause for the MIL light. I have run 87 Octane in the past when I couldn't get a higher octane. This will affect performance, but the ECU compensates for the lower octane. Performance is the only hit you'll take. In my experience, this will not activate the MIL.

Whenever the MIL light comes on, the ECU stores a code for the cause of the malfunction. Using a code scanner or laptop software/hardware will pull the code and tell you where to start looking for the cause.

If you don't have access to a code scanner, take it to the dealer. This will be covered under warranty if there is no evidnece of abuse. Good luck!

 

hey the light will go off eventually... Don't worry about it. I did the same thing to mine a while back by not tightening the gas cap enought times. I finally figured out what I did. It took more than 3 trips though before it went off. I think it was about 5 or 6 times

 

Ok, well I reset the ECU by taking the fuse out and all. I retightened the fuel cap and just for peace of mind I even dropped a 104 octane booster. So, all in all the results are positive. The indicator loght is gone. Thanks for all of the love guys/gals. Now, I get to go out and have some fun under the sun!

-daniel