Dreaded Service Engine Soon (SES) Light Illuminated
 

So I was driving a client around last night in the city here and all of the sudden my SES light came on (solid not blinking). I have never seen it come on before so it startled me. Nothing seemed strange about the way the car is running. Plenty of power, check control OK, and engine temp normal. I should have checked the digital temp on the cluster diagnostics tho.

So after driving a short distance to our destination the car sat for a couple of hours. I was hoping the light might reset when I started the car again but no luck.

When I got the car home I poked around in the engine compartment - seemed a little hot but nothing I can see out of the ordinary. No leaks, strange sounds or anything. No wierd burning smells or anything, just the normal smell of warm rubber hoses and such. I will check the coolant level today, but there were no check control messages concerning this.

The manual states:

That's from the 2004 manual, my (2000) manual was similar verbiage but mentioned that damage could occur to the catalytic converter with continued use with SES light on. After searching around on the forum it looks like a fault code could indicate and issue with something other than emissions control system.

I did read the post regarding SES in the How To section.

I think I am going to try and reset the ECU by unplugging the battery for a while to see if that will clear the light, but of course it may come back if there is some persistent problem.

I ordered a ScanGauge II OBD Scanner to check the codes and it will reset them as well if it's something minor. Is there a way to pull codes from the onboard diag?

So - my question to you all is. My pops is coming into town and I need to drive around a little bit. How safe is it to drive the car?

Autozone will read the codes at no cost. They even have a loaner program where you essentially buy the OBD-II scanner and then return it when you're done. If you've got one nearby you might think about cancelling the one you ordered.

With that said BMW told me it was OK to drive the vehicle with the SEL light illuminated unless it is flashing (indicating an engine misfire). Aside from increased emissions output an illuminated SEL shouldn't cause any harm.

Safe to drive. Check your gas cap is tight, as that is one of the frequent causes. Don't try clearing it, there is no point. Read the codes, or better yet, get them read, and you will have pointers to what the problem is. The light isn't the problem, it is a flag that there is a problem. Until you rectify the root cause, it will come back on.

Thanks guys for the sound advice! I think I will do the autozone loaner thing for now. I am going to keep the one I ordered since it's useful and also has vehicle data. I need more whiz-bang lights and gadgets!

One thing tho - let's say it's something like the gas cap. If I "fix" the problem will the light just go away or will it stay until manually cleared by a scanner device?

--Thanks!!!

Kragen and Napa BLOW.

Kragen only sells them and will not perform the diag for free. Napa does neither. I miss having an Autozone on every block like I did in AZ :-(

If it is the gas cap loose it will reset by itself once you tighten the gas cap (it can take a few hours)

That's really strange. I mistakenly drove briefly not that long ago with the gas cap completely off and I didn't get any lights. I will re-seat it and see what happens.

Coolant and Engine Oil levels are fine. Cleaned gas cap and filler hole area still getting SES light. As far as I can tell the engine sounds pretty normal to me.

My SES light came on and it turned out to be 02 sensors, it didn't really drive differently at all, so get the codes checked, mine said aging precat 02 sensor.

So... the light turned off today! Maybe it was the gas cap - I hadn't been driving the truck for very long periods of time. Still curious exactly what it was - either way I'll take it!