Is a "service engine" light the same as a "check engine" light?

Dear Car Talk

Dear Car Talk | Mar 01, 1995

Dear Tom and Ray:

I own a 1992 Saturn SL1 with 58,000 miles on it. It's a wonderful car that has very few problems, but I do have one concern. Periodically, my "Service Engine Soon" light comes on, stays a while, and blinks off. My oil is full and recently changed, and all the other bottles are full. What is causing this, and is it serious?

RAY: This light is telling you that a certain maintenance procedure is required right now, Nikki. We'll tell you how to do it.

TOM: Start by going out to your Saturn and unlocking the passenger door, not the driver's door. Then get in.

RAY: Right in front of you you'll see the flip down door to the glove compartment. Open it.

TOM: Now rummage through the gas card receipts, the Sleepy LaBeef cassettes, and the pistachio shells, and reach down towards the bottom of the glove compartment.

RAY: If you feel around down there, you'll feel a flat, somewhat shiny object. Remove it.

TOM: That's the Owner's Manual. And the procedure you need to perform is to read it.

RAY: I realize it's not exactly a Michael Crighton thriller, but there's a lot of very useful information in there, including the answer to your question.

TOM: What you'll find is that the "Service Engine Soon" light is what many other cars call the "Check Engine" light. It's not an emergency, but it means that one of the signals going into the computer is not reading what it's supposed to be reading.

RAY: And the reason could be anything from a bad sensor to a bonefide engine problem. Your mechanic will be able to tap into the computer and read the "trouble code" on his scanner and figure out what it is. That's why it says "Service Engine Soon."

TOM: I think they changed the name because when the "Check Engine" light came on, people like my brother would get out, check the engine, and if the engine was still there, they'd get back in the car and drive away. So I guess "Service Engine Soon" is for people who took the "Check Engine" light too literally.

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