That's where I'm from, originally.

 

Don't know if this helps or not...we have a friend who is a factory Ford mechanic where they bulid the Police Interceptors. His job...post production detail and repair. He has a set up not unlikea dealer mechanic at the end of the line. He says plenty of cars glow with the Check engine light right off the line. First place he looks is the gas cap. He claims nicks on the filler neck from the screw guns or what ever create a bad seal and the evap system codes out. Not always the gas cap and filler neck but very often it is and his job is done in 10 minutes. Sometimes it takes him days to find. He's not on the clock though because they find that Police Departments don't like taking delivery of cars with the check engine light on.

 

SES and CHECK ENGINE lights can be turned on for many reasons. after 1996 a loose gas cap will turn it on.GM cars have had this trouble-some light since 1981. It can be turned on by many differenent things,BUT THE MAIN CONCERN IS THAT DAMN LIGHT IS BACK ON.Sometime it because it was misdiagnosed and the same code came back. At other time something else failed a short time later.The feds mandated ses light on 96 and later car designed to operate in US ses light should light up and time car won't pass emission test, and flash if cat.conv. is in danger.The computer monitors many things there over 50 codes that can turn light on, but there is only one light.I did know of one shop years ago the fixed the light by taking bulb out, and would release a tech who would do it.It would never light again,period.Patrons would never know a sensor went bad and the car could quit and not restart,usually at the most inconvienent time and place,but the good thing was that annoying light was on.The mil is annoying and I do understand the frustraition of it coming on,especially if it is the same thing over and over.But it is what it is,required by law and in the customers interest.And by the way loose and missing gas cas #1 cause of SES lights. And that is all I got to say about that.

 

My '04 had the check engine light come on. The car completely shut off (about 58,000 miles). A friend of mine diagnosed it as the throttle body. I had that replaced and 50 miles later, the light came back on again. I brought it to my dealer to further diagnose the problem. They first said I had a bad battery so I had to spend $390.00 to replace that. 50 miles later, the laigh came on again. They replaced the ignition switch. Light came on again. They replaced a relay for the ignition switch. Light on again. They replaced the PCM. Now driving it for about 300 miles the light is on again. I don't know what they will find next. Cadillac tech assistance has been telling them to do all this and the problem keeps reacurring. Anyone know what the lemon law would be for this?

 

Look on your paper work does it list code(s) that was set, is the same code resetting? List code(s) and correction.