There was a thread about this a couple of months ago. The SES light on my 2k2 sometimes is very faintly visible, but only when the headlights are on. When the lights are turned off, the SES light is still lit. During the day, if I drive into the garage, the light is not on. The car has definitely not dropped any codes, because the light would be much brighter. Anyone have any insight?

 

same here. no problems. nothing to worry about.

 

Right, I know its nothing to worry about, but it is annoying and shouldn't on. So why is it on?

 

I noticed the same thing after I reset my 1st. SES right after I put in a Stillen intake. We couldn't figure out what the code was (see my post Does anyone know what this DTC is for: P1456 ) so we just reset it. Now it is back on and I'm going to the dealer.

My take on it is it has something to do with 1 of to tests in the drive cycle. The ECU is always running emissions test in what is called a "drive cycle" it must finish certian tests before it can move on to others and it can some times take several months if not more to finish.
Have you reset your ECU recently?

 

No, I haven't reset the ECU. But this seems to be different than what your are experiencing. In this case, the light is only just visible in the dark, and not at all visible in the daylight. It only seems to come on when the panel lights are on. I had originally thought it was light leakage from the instrument lights, but when those are turned off the SES is still illuminated. I had the dealer check if there were any codes, and there were none. He could not duplicate the problem, which is not surprising because it is intermitent. I believe the problem is due to some inductance/interference in the wires that are connected to the SES light.

 

I have the same prob. The light is always on, you just cant see it in the daylight. I havn't looked at a wiring diagram but on the older cars the only thing that can turn the light on is the computer, it supplies the ground. I havn't taken mine in yet but I bet a bunch of us will be getting new PCM's.

 

No my light was faintly visible all the time until it went away for about 2mo. then the SES came back on brite last week. I misunderstood what you were saying based on this sentence.

How long have you had the car?

 

4mos.

 

Probably just a bad trace somewhere....

 

In that case I still think it has something to do with 1 of the drive cycle tests. Give it a week and see if it still faintly on. Also check this out ENGINE DIAGNOSTICS: ZEROING IN ON OBD II about 1/2 way down is a heading titled READINESS FLAGS.

I know for a fact 1 of the tests for earlier Max's needs the car to be driven at 25mph for 2min. I know that doesn't happen to often in my car .