Check Engine Light

I had my first Check Engine Light experience today. This is my 10th car in 38 years, and even that 1966 Mustang that cut off in the intersection never gave me the experience of the Check Engine Light.

But I am a faithful listener of Click and Clack, the Tappet Brothers on Car Talk every weekend on NPR. I have been thoroughly schooled so that I know to go directly to my dealer when I see that light.

Well, it was 1:30 on a Friday afternoon, the day before I planned to drive 600 miles to see the grands. If I hadn't gone out to the ATM, and gas station, would that light have waited until I got down the road at 6AM on Saturday?...horrors!

The rain started just as I was pulling away from the ATM, and it came hard and blustery, like the bottom had fallen out. I turned the corner through a new puddle, a real splasher, when the light came on. The message on the dash read "Replace Gas Cap."

I continued to the gas station, and found that the gas cap was indeed loose, inside the little door. I have to confess that I intentionally left it loose because the last few times I got gas, I had to ask someone to help me get the thing off. I had thought about going to the dealer about it then, but it seemed too wimpy not to wait until my next regular service. So I pumped my gas and screwed that cap on. Back in the car, the light came back on.

So on I went to the dealer...the Cadillac dealer. I started thinking about the fact that I had ignored all those letters telling me that my warranty was about to expire. And I started thinking about the GM bankruptcy, and wondering if my dealer was still there. They are. It's good to have someone who knows you on a Friday afternoon. I told my regular guy that I planned to drive to Atlanta in the morning. So he put me in the line for diagnostics. Meanwhile I had pulled the owner's manual out. This is what it said:


If the Light is on Steady

You may be able to correct the emission system malfunction by considering the following:

Did you recently put fuel in your vehicle?

If so, reinstall the fuel cap, making sure to fully install the cap. Blah blah blah. A loose or missing fuel cap will allow fuel to evaporate into the atmosphere. A few driving trips with the cap properly installed should turn the light off.

Did you just drive through a deep puddle of water?

If so, your electrical system may be wet. The condition will usually be corrected when the electrical system dries out. A few driving trips should turn the light off.

Well, they ran the diagnostics, and got error code P0455 - Faulty Gas Cap. They gave me a new cap, no charge.

Lesson for Sarah: Next time RTFM...Read the F#-ing Manual. I could have saved myself the 2 hour wait.

But I'm also wondering why...if the car knew what was going on in the first place, why didn't it shut off that light after I screwed the cap on tight?