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Check engine light. Fact or fiction?

I own a 2006 Nissan Xterra. My check engine light recently came on. My car only has 30K on it. Should I take the car in ASAP or wait another month and a half until I have to take it in for an oil change? Are these lights triggered by the dealership to go off at a certain mileage point in order to sell the consumer stuff they don’t need. Also, this morning was the first time the outside temperature dipped below freezing in my area so I’m wondering if that has something to do with it. Any insight on this would be appreciated. Thanks

Check Engine Lights are a fault in the emissions control system. You can definitely wait for the oil change if its simply steady lit. If it is ever flashing drive it immediately to a repair shop. Flashing check engine light means something is severely wrong.

Waiting long periods like a half a year before addressing can sometimes damage expensive emissions components like the cat converter and O2 sensor(s).

Your paranoia about the dealer and check engine lights is baseless. Some car have separate lights usually labeled maintenance reminders.

Take it to a place like AutoZone or Advance Auto and have them read the codes. They should do this for free, but they may also charge you, I’m not sure. When you get the codes read, post on here the exact wording and codes they give you

In my experience, a constantly glowing check engine light usually indicates a fault that has caused the fuel control system to go ‘open loop’ where it ignores its sensor inputs and runs at a default setting. The engine may seem to be running OK, but your gas mileage may be terrible. Waiting for that next oil change may cost you $ in unnecessary fuel consumption.

I concur that you are likely wasting gas while the CEL is illuminated, but as long as the engine is running smoothly, you can safely wait until your next service appt. The real danger sign is when the CEL is flashing,as that indicates the need for immediate attention.

Incidentally–Is anyone from the dealership following you? Have you checked to make sure that they aren’t watching you?


Are these lights triggered by the dealership to go off at a certain mileage point in order to sell the consumer stuff they don’t need.

No, the dealership does not trigger the light. In fact, if you live in a state where emission inspections are required your car will fail the inspection simply due to the CEL being on. Take bscar’s advice and get those codes read.

Is your car under warranty? If so go straight to the dealer and let them fix it. It is not your problem what is wrong or why the light came on, for now all it means is the dealer has to fix it.

Note If the light is flashing, it means there is something serious and something that might cause additional damage. Ignoring it may invalidate your warrantee.

I suggest you check your owner’s manual. In some cars that flashing light means pull over NOW or risk serious damage. That means pull off to the side of the road where it is safe and not try to make it to the next exit or home.

If it is not under warranty then find a local independent mechanic. Local mechanics are not “better” than the dealer, but they are better in some ways (dealer better in some) and they are almost always cheaper. Sorry usually no TV and free coffee while you wait.

Just out of curiosity - did you fill up with gas within a day or so of the light coming on ?
If so check the gas cap - it should click three times as you turn it to indicate a good seal .
If the cap wasn’t tight then the light will go off after you have run the car two or three times after tightening it .

The best advice I’ve seen here is to use what’s out there and free. Autozone or other retail stores will check your code for free and tell you what it means. Takes as long as 10 minutes and might relieve you of the stress.

Dealers will save money at all costs. Here’s how they get “electronic rebates”. If the car runs great and has really low emissions, the light will come on. When you bring it in to the dealer, they will drain out 10% of the platinum from the catalytic converter and cash in. Saving the environment is good but not as good as money. Another drawback of those warning lights is that when they come on I can’t concentrate on my text messaging. Stuff like that could cause an accident.

Like You Are Right On! They Take 10% Of Your Coolant, Too!
Don’t believe me? Next time you drive several miles to the dealer for service, check the coolant in the reservoir, after the car’s been sitting a few minutes. When you go to pick it up at the end of the day, check it again. I’ll bet some of your coolant is missing! The dealers do this legally! They have discovered a loophole in the Laws of Thermodynamics.

Let’s hope the OP can feel that giant tugging on his lower extremity.

I’ve forgotten the question. IS the question, “Are car dealers evil?”, or is the question, “Do check engine lights lie?”? The answer is, “Yes, check engine lights are evil!”.

In my experience, CELs can either mean serious issues or nothing at all. I’d see if you can go by a car parts place to have it scanned for free so you at least know what you’ll be facing.